Facile synthesis of Ag-ZnO core–shell nanostructures with enhanced photocatalytic activity

Enhancement of effluent degradation by zinc oxide, carbon nitride, and carbon xerogel trifecta on brass monoliths

In recent years, heterogeneous photocatalysis has emerged as a promising alternative for the treatment of organic pollutants. This technique offers several advantages, such as low cost and ease of operation. However, finding a semiconductor material that is both operationally viable and highly active under solar irradiation remains a challenge, often requiring materials of nanometric size. Furthermore, in many processes, photocatalysts are suspended in the solution, requiring additional steps to remove them. This can render the technique economically unviable, especially for nanosized catalysts. This work demonstrated the feasibility of using a structured photocatalyst (ZnO, g-C3N4, and carbon xerogel) optimized for this photodegradation process. The synthesized materials were characterized by nitrogen adsorption and desorption, X-ray diffraction (XRD), and diffuse reflectance spectroscopy (DRS). Adhesion testing demonstrated the efficiency of the deposition technique, with film adhesion exceeding 90%. The photocatalytic evaluation was performed using a mixture of three textile dyes in a recycle photoreactor, varying pH (4.7 and 10), recycle flow rate (2, 4, and 6 L h-1), immobilized mass (1, 2, and 3 mg cm-2), monolith height (1.5, 3.0, and 4.5 cm), and type of radiation (solar and visible artificials; and natural solar). The structured photocatalyst degraded over 99% of the dye mixture under artificial radiation. The solar energy results are highly promising, achieving a degradation efficiency of approximately 74%. Furthermore, it was possible to regenerate the structured photocatalyst up to seven consecutive times using exclusively natural solar light and maintain a degradation rate of around 70%. These results reinforce the feasibility and potential application of this system in photocatalytic reactions, highlighting its effectiveness and sustainability.

Boosted charge separation via Ce2S3 over dual Z-scheme ZnO-Ce2S3-MnO2 core double-shell nanocomposite for the degradation of diverse dye pollutants

Herein, core double-shell direct dual Z-scheme ZnO-Ce2S3-MnO2 nanocomposite was synthesized via a hydrothermal route along with pure ZnO, Ce2S3, MnO2, and characterized by numerous characterization tools for application in synthetic dyes degradation. The XRD, Raman, and FTIR analyses have confirmed the nanocomposite formation. TEM images exhibited the core double-shell morphology with an average particle diameter of 81 nm and stacking of ZnO, Ce2S3, and MnO2. EDX confirmed the existence of desired elements in the grown composition. The varied oxidation states, presence of defects, and fast charge transfer were also revealed from XPS, PL, and EIS. The ZnO-Ce2S3-MnO2 nanocomposite has an optical energy bandgap of 2.84 eV, capable of decomposing harmful dyes with excellent efficiency, 99.81% MB, 97.62% MO, 88.5% MR, and 58.9% EY in 40 min sunlight exposure. The effect of several operating parameters is also observed and obtained results showed the optimal catalyst dose was 20 mg, pH of 8, and dye concentration of 10 ppm. The scavenger's experiment suggests that •O2- and •OH are the main active radicals in the photodegradation reaction which is also evident in the dual Z-scheme formation. The MnO2 and ZnO layers covered the Ce2S3 (core) and dual Z-scheme formation allows rapid kinetics of redox reaction and provides plenteous channels for transfer of photo-generated charge carriers during photocatalysis. Thus, core double-shell direct dual Z-scheme photocatalysts having inorganic components could be an excellent choice for photocatalysis at the industrial level, particularly for water purification.

High performance and recyclable Ag/ZnO/PM substrate for the detection of organic pollutants

A sensitive and recyclable substrate was fabricated through in situ reduction of silver nanoparticles (NPs) on zinc oxide nanorods (NRs). The prepared silver nanoparticles/zinc oxide nanorods/polyamide mesh (Ag/ZnO/PM) substrate exhibited not only excellent surface-enhanced Raman scattering (SERS) performance to R6G with a limit of detection (LOD) of 10-12 M, mainly attributed to the synergistic effect of the suitable size and the nanoscale gaps of the Ag NPs to produce local surface plasmon resonance (LSPR), but also outstanding self-cleaning property via UV irradiation due to its significant photocatalytic property based on the non-equilibrium carriers generated by ZnO and the presence of Schottky junctions between Ag and ZnO. The substrate showed good recycling stability even after five cycles. Furthermore, the successful recyclable application of Ag/ZnO/PM for tetracycline hydrochloride (TC) detection with high sensitivity further suggested that it is a promising candidate for constructing a portable SERS platform to detect organic pollutants.

Synthesis and Antimicrobial Activity of 3D Micro-Nanostructured Diatom Biosilica Coated by Epitaxially Growing Ag-AgCl Hybrid Nanoparticles

The 3D (three-dimensional) micro-nanostructured diatom biosilica obtained from cultivated diatoms was used as a support to immobilize epitaxially growing AgCl-Ag hybrid nanoparticles ((Ag-AgCl)NPs) for the synthesis of nanocomposites with antimicrobial properties. The prepared composites that contained epitaxially grown (Ag-AgCl)NPs were investigated in terms of their morphological and structural characteristics, elemental and mineral composition, crystalline forms, zeta potential, and photoluminescence properties using a variety of instrumental methods including SEM (scanning electron microscopy), TEM (transmission electron microscopy), EDX (energy-dispersive X-ray spectroscopy), XRD (X-ray powder diffraction), zeta-potential measurement, and photoluminescence spectroscopy. The content of (AgCl-Ag)NPs in the hybrid composites amounted to 4.6 mg/g and 8.4 mg/g with AgClNPs/AgNPs ratios as a percentage of 86/14 and 51/49, respectively. Hybrid nanoparticles were evenly dispersed with a dominant size of 5 to 25 nm in composite with an amount of 8.4 mg/g of silver. The average size of the nanoparticles was 7.5 nm; also, there were nanoparticles with a size of 1-2 nm and particles that were 20-40 nm. The synthesis of (Ag-AgCl)NPs and their potential mechanism were studied. The MIC (the minimum inhibitory concentration method) approach was used to investigate the antimicrobial activity against microorganisms Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus. The nanocomposites containing (Ag-AgCl)NPs and natural diatom biosilica showed resistance to bacterial strains from the American Type Cultures Collection and clinical isolates (diabetic foot infection and wound isolates).

Single-Atom Ru Catalyst-Decorated CNF(ZnO) Nanocages for Efficient H2 Evolution and CH3OH Production

The presence of transition-metal single-atom catalysts effectively enhances the interaction between the substrate and reactant molecules, thus exhibiting extraordinary catalytic performance. In this work, we for the first time report a facile synthetic procedure for placing highly dispersed Ru single atoms on stable CNF(ZnO) nanocages. We unravel the atomistic nature of the Ru single atoms in CNF(ZnO)/Ru systems using advanced HAADF-STEM, HRTEM, and XANES analytical methods. Density functional theory calculations further support the presence of ruthenium single-atom sites in the CNF(ZnO)/Ru system. Our work further demonstrates the excellent photocatalytic ability of the CNF(ZnO)/Ru system with respect to H2 production (5.8 mmol g-1 h-1) and reduction of CO2 to CH3OH [249 μmol (g of catalyst)-1] with apparent quantum efficiencies of 3.8% and 1.4% for H2 and CH3OH generation, respectively. Our studies unambiguously demonstrate the presence of atomically dispersed ruthenium sites in CNF(ZnO)/Ru catalysts, which greatly enhance charge transfer, thus facilitating the aforementioned photocatalytic redox reactions.

Photocatalytic fuel cell based on integrated silicon nanowire arrays/zinc oxide heterojunction anode for simultaneous wastewater treatment and electricity production

Photocatalytic fuel cells (PFCs) convert organic waste into electricity, thereby providing a potential solution for remediating environmental pollution and solving energy crises. Most PFCs for energy generation applications use powder photocatalysts, which have poor mechanical stability, high internal resistance, and may detach from the substrate during reactions, leading to unstable performance. Integrated photoelectrodes can overcome the drawbacks of powder catalysts. In this study, an integrated photoanode was prepared based on a silicon nanowire arrays/zinc oxide (Si NWs/ZnO) heterojunction by combining metal-assisted chemical etching (MACE) and hydrothermal methods. The resulting photoanode was used to assemble a PFC for simultaneous electricity generation and Rhodamine (RhB) dye wastewater degradation. This PFC showed excellent cell performance under irradiation, with a short-circuit current density of 0.183 Am-2, an open-circuit voltage (OCV) of 0.72 V, and a maximum power density of 0.87 W m-2. It could also be used continuously 20 times while degrading > 90% of RhB. This performance was ascribed to the three-dimensional (3D) structure and large surface area of Si NWs, as well as the matched band structure of ZnO, which facilitated the efficient separation and transport of photogenerated carriers in Si NWs/ZnO. The integrated structure also shortened the carrier transport pathways and suppressed carrier recombination. This research provides a foundation for the development of efficient, stable, low-cost, small-scale PFCs.

In situ fabrication of Ag decorated porous ZnO photocatalyst via inorganic-organic hybrid transformation for degradation of organic pollutant and bacterial inactivation

In this study, in situ silver (Ag) - porous ZnO photocatalysts were synthesized via solvothermal and post-annealing treatment. The formation of the porous ZnO structure due to the removal of organic moieties from the inorganic-organic hybrids Ag-ZnS(en)0.5 during the annealing process. The optimal Ag-ZnO photocatalyst showed excellent photocatalytic degradation activity, with 95.5% orange II dye and 97.2% bisphenol A (BPA) degradation under visible light conditions. Additionally, the photocatalytic inactivation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) led to a 97% inactivation rate after 2 h under dark conditions. Trapping experiments suggest that the superoxide anion (O2-) radicals are the main active species to degrade the organic dye. The improved photocatalytic dye degradation activity and inactivation of bacteria were attributed to the synergistic effect of Ag and porous ZnO structure, increased surface area, and efficiently separated the photoexcited charge carriers. This work could provide an effective strategy for the synthesis of porous structures toward organic pollutant degradation and bacterial inactivation in wastewater.

Sustainable bioactivity enhancement of ZnO-Ag nanoparticles in antimicrobial, antibiofilm, lung cancer, and photocatalytic applications

Cancer, microbial infections, and water pollution are significant challenges the modern human population faces. Traditional treatments for cancer and infections often have adverse effects and ecological consequences, while chemical methods for water decontamination can produce harmful byproducts. Metal nanoparticles, particularly zinc oxide (ZnO) and silver (Ag) nanoparticles, show promise in addressing these issues. However, doping Ag on ZnO NPs may synergistically enhance biomedical and therapeutic effects with fewer adverse consequences and improved photocatalytic properties for wastewater treatment. This study aimed to create ZnO and ZnO-Ag nanoparticles through green synthesis and compare their anticancer, antimicrobial, and photocatalytic activity mechanisms. XRD studies determined the crystal diameters of ZnO NPs and ZnO-Ag NPs to be 12.8 nm and 15.7 nm, respectively, with a hexagonal wurtzite structure. The XPS and EDS analyses confirmed the presence of Ag on the ZnO NPs. ZnO NPs and ZnO-Ag NPs exhibited low aggregation in aqueous suspensions, with zeta potentials of -20.5 mV and -22.7 mV, respectively. Evaluating antimicrobial and antibiofilm activity demonstrates that ZnO-Ag NPs have superior potential to ZnO NPs and standard antibiotic drugs against E. coli, S. typhi, B. subtilis, S. aureus, C. albicans, and A. niger. The results of the in vitro cytotoxicity test indicated that on the NCI-H460 lung cancer cell line, ZnO NPs and ZnO-Ag NPs demonstrated IC50 values of 40 μg mL-1 and 30 μg mL-1, respectively. The photocatalytic degradation of methylene blue under direct sunlight revealed that ZnO and ZnO-Ag NPs degraded MB by 98% and 70% in 105 min, respectively. These results show that these nanomaterials may have great potential for treating the aforementioned issues.

Comparative study of zinc oxide nanocomposites with different noble metals synthesized by biological method for photocatalytic disinfection of Escherichia coli present in hospital wastewater

Binary zinc oxide (ZnO) nanocomposites with different noble metals, silver (Ag) and ruthenium (Ru), were prepared from an aqueous leaf extract of Callistemon viminalis. The biosynthesized photocatalysts were characterized and examined for their photocatalytic disinfection against Escherichia coli isolated from hospital wastewater. The influence of the different noble metals showed a difference in physicochemical characteristics and photocatalytic efficiency between Ag-ZnO and Ru-ZnO. The photocatalytic degradation of methylene blue and photocatalytic disinfection were found to be in the order Ag-ZnO > Ru-ZnO > ZnO. The photocatalytic disinfection of Ag-ZnO reached a 75% reduction in 60 min, compared to 34 and 9% reductions of Ru-ZnO and ZnO, respectively. The kinetic reaction rate for the photocatalytic disinfection of Ag-ZnO was found to be 2.8 times higher than that of Ru-ZnO. The outstanding photocatalytic activity of Ag-ZnO over Ru-ZnO was attributed to higher crystallinity, greater UVA adsorption capacity, smaller particle size, and the additional antimicrobial effect of Ag itself. The C. viminalis-mediated Ag-ZnO nanocomposites can be a potential candidate for photocatalytic disinfection of drug-resistant E. coli in hospital wastewater.

New Eco-Friendly and Low-Energy Synthesis to Produce ZnO Nanoparticles for Real-World Scale Applications

This paper presents an original and sustainable method for producing ZnO nanoparticles (NPs) in response to global challenges (low energy requirements, low environmental impact, short production times, and high production yield). The method is based on an ion exchange process between an anionic resin and an aqueous ZnCl2 solution; it operates in one step at room temperature/ambient pressure without the need for complex apparatus or purification steps. From the kinetics, we observed the formation of pure simonkolleite, a zinc-layered hydroxide salt (Zn5(OH)8Cl2·H2O), after only 5 min of reaction. This compound, used elsewhere as a ZnO precursor after calcination at high temperatures, here decomposes at room temperature into ZnO, allowing extraordinary savings of time and energy. Finally, in only 90 min, pure and crystalline ZnO NPs are obtained, with a production yield > 99%. Several types of aggregates resulting from the self-assembly of small hexagonal platelets (solid or hollow in shape) were observed. Using our revolutionary method, we produced almost 10 kg of ZnO NPs per week without any toxic waste, significantly reducing energy consumption; this method allows transferring the use of these unique NPs from the laboratory environment to the real world.

Facile synthesis of robust Ag/ZnO composites by sol-gel autocombustion and ion-impregnation for the photocatalytic degradation of sucrose

Metallic Ag nanoparticles decorated on ZnO photocatalysts were prepared by facile sol-gel autocombustion followed by ion-impregnation. Electron microscopy studies revealed the presence of impregnated Ag as nanoparticles on ZnO surfaces, which affected the microstructure of ZnO particles. XRD patterns of Ag/ZnO composites confirmed the metallic phase of Ag. No peak shift for ZnO phase peaks suggests that the impregnated Ag was barely incorporated into the ZnO lattice. Consequently, DRS spectra of Ag/ZnO composites revealed the same absorption edges and E_g for pure and Ag/ZnO. The photocatalytic activity of Ag/ZnO composites for sucrose degradation under UV light was 40% higher than that of pure ZnO. Metallic Ag nanoparticles on the ZnO surface suppressed the surface defects and the recombination of photoexcited electrons and holes. The highest activity with 100% degradation of 100 ppm sucrose (1200 µg of carbon) within 105 min was achieved using ZnO with 10% w/w Ag (10% Ag/ZnO). Ag L3-edge XANES spectra of fresh and spent Ag/ZnO catalysts confirmed the stability of metallic Ag after the usage. The Ag/ZnO catalyst could be used for 5 cycles without losing photocatalytic activity. The Ag/ZnO catalyst was utilized to degrade sugar-contaminated condensate from the sugar mill. 10% Ag/ZnO revealed the highest photocatalytic performance, capable of degrading 90% of sugar in the condensate within 90 min.

Developing low-cost nanohybrids of ZnO nanorods and multi-shaped silver nanoparticles for broadband photodetectors

Photodetectors are essential elements for various applications like fiber optic communication systems, biomedical imaging, and so on. Thus, improving the performance and reducing the material costs of photodetectors would act as a motivation toward the future advancement of those applications. This study introduces the development of a nanohybrid of zinc oxide nanorods (ZnONRs) and multi-shaped silver nanoparticles MAgNPs through a simple solution process; in which ZnONRs are hybridized with MAgNPs to enable visible absorption through the surface plasmon resonance (SPR) effect. The photodetector based on ZnONRs/MAgNPs is responsive to visible light with representative wavelengths of 395, 464, 532 and 640 nm, and it exhibits high responsivity (R), photoconductive gain (G) and detectivity (D). The maximum R is calculated from the fitting curve of the responsivity-power relation with the value of 5.35 × 10³ (mA W^-1) at 395 nm excitation. The highest G and D reach 8.984 and 3.71 × 10¹⁰ Jones at that wavelength. This reveals the promise of our innovative broadband photodetector for practical usage.

Impact on the Photocatalytic Dye Degradation of Morphology and Annealing-Induced Defects in Zinc Oxide Nanostructures

In this study, three different morphologies, nanoflower (NF), nano sponge (NS), and nano urchin (NU), of zinc oxide (ZnO) nanostructures were synthesized successfully via a mild hydrothermal method. After synthesis, the samples were annealed in the atmosphere at 300, 600, and 800 °C. Although annealing provides different degradation kinetics for different morphologies, ZnO NS performed significantly better than other morphologies for all annealing temperatures we used in the study. When the photoluminescence, electron paramagnetic resonance spectroscopy, BET surface, and X-ray diffraction analysis results are examined, it is revealed that the defect structure, pore diameter, and crystallinity cumulatively affect the photocatalytic activity of ZnO nanocatalysts. As a result, to obtain high photocatalytic activity in rhodamine B (RhB) degradation, it is necessary to develop a ZnO catalyst with fewer core defects, more oxygen vacancies, near band emission, large crystallite size, and large pore diameter. The ZnO NS-800 °C nanocatalyst studied here had a 35.6 × 10^-3 min^-1 rate constant and excellent stability after a 5-cycle photocatalytic degradation of RhB.

Aluminium doped ZnO nanostructures for efficient photodegradation of indigo carmine and azo carmine G in solar irradiation

Aluminium doped zinc oxide (AZO) nanomaterials (AlxZn1-xO) with x fraction varying as 0.02 and 0.04 were synthesized using the auto-combustion method using glycine as a fuel. The synthesized catalysts were characterized with X-ray diffraction (XRD), UV–Visible Spectroscopy (UV–Vis), Raman spectroscopy, Photoluminescence (PL) spectroscopy, and High Resolution Transmission Electron Microscopy (HR-TEM). XRD results showed that synthesized materials possessed good crystallinity, while UV–VIS was employed to find the band gaps of synthesized materials. Raman was used to determine the vibrational modes in the synthesized nanoparticles, while TEM analysis was performed to study the morphology of the samples. Industrial effluents such as indigo carmine and azo carmine G were used to test the photodegradation ability of synthesised catalysts. Parameters such as the effect of catalyst loading, dye concentration and pH were studied. The reduction in crystallite size, band gap and increased lattice strain for the 4% AZO was the primary reason for the degradation in visible irradiation, degrading 97 and 99% equimolar concentrations of indigo carmine and azo carmine G in 140 min. The Al doped ZnO was found to be effective in faster degradation of dyes as compared to pure ZnO in presence of natural sunlight.

Application Prospects of MXenes Materials Modifications for Sensors

The first two-dimensional (2D) substance sparked a boom in research since this type of material showed potential promise for applications in field sensors. A class of 2D transition metal nitrides, carbides, and carbonitrides are referred to as MXenes. Following the 2011 synthesis of Ti3C2 from Ti3AlC2, much research has been published. Since these materials have several advantages over conventional 2D materials, they have been extensively researched, synthesized, and studied by many research organizations. To give readers a general understanding of these well-liked materials, this review examines the structures of MXenes, discusses various synthesis procedures, and analyzes physicochemistry properties, particularly optical, electronic, structural, and mechanical properties. The focus of this review is the analysis of modern advancements in the development of MXene-based sensors, including electrochemical sensors, gas sensors, biosensors, optical sensors, and wearable sensors. Finally, the opportunities and challenges for further study on the creation of MXenes-based sensors are discussed.

Green synthesis of ZnFe2O4@ZnO nanocomposites using Chrysanthemum spp. floral waste for photocatalytic dye degradation

The occurrence of textile dyeing wastewater discharged into the environment has been recently increasing, resulting in harmful effects on living organisms and human health. The use of green nanoparticles for water decontamination has received much attention. Floral waste can be extracted with the release of natural compounds, which act as reducing and stabilizing agents during the biosynthesis of nanoparticles. Herein, we report the utilization of Chrysanthemum spp. floral waste extract to synthesize green ZnFe₂O₄@ZnO (ZFOZx) nanocomposites for the photocatalytic degradation of Congo red under solar light irradiation. The various molar ratio of ZnFe₂O₄ (0-50%) was incorporated into ZnO nanoparticles. The surface area of green ZFOZx nanocomposites was found to increase (7.41-42.66 m² g^-1) while their band gap energy decreased from 1.98 eV to 1.92 eV. Moreover, the results exhibited the highest Congo red dye degradation efficiency of 94.85% at a concentration of 5.0 mg L^-1, and a catalyst dosage of 0.33 g L^-1. The ^•O₂^- reactive species played a vital role in the photocatalytic degradation of Congo red dye. Green ZFOZ3 nanocomposites had good recyclability with at least three cycles, and an excellent stability. The germination results showed that wastewater treated by ZFOZ3 was safe enough for bean seed germination. We expect that this work contributes significantly to developing novel green bio-based nanomaterials for environmental remediation as well as reducing the harm caused by flower wastes.

The CuO and AgO co-modified ZnO nanocomposites for promoting wound healing in Staphylococcus aureus infection

Bacterial has become a common pathogen of humans owing to their drug-resistant effects and evasion of the host immune system, with their ability to form biofilm and induce severe infections, a condition which has become a primary public health concern globally. Herein, we report on CuO@AgO/ZnO NPs antibacterial activity enhanced by near-infrared (NIR) light which was effective in the elimination of Staphylococcus aureus and the Pseudomonas aeruginosa. The CuO@AgO/ZnO NPs under NIR significantly eradicated S. aureus and its biofilm and P. aeruginosa in vitro, and subsequently exhibited such phenomenon in vivo, eliminating bacteria and healing wound. This demonstrated the combined intrinsic antibacterial potency of the Cu and Ag components of the CuO@AgO/ZnO NPs was enhanced tremendously to achieve such outcomes in vitro and in vivo. Considering the above advantages and facile preparation methods, the CuO@AgO/ZnO NPs synthesized in this work may prove as an important antibacterial agent in bacterial-related infection therapeutics and for biomedical-related purposes.

Volatile organic compounds in water matrices: Recent progress, challenges, and perspective

Volatile organic compounds (VOCs) are a group of organic compounds that have a molecular structure containing carbon and their chemical properties allow them to be easily converted to steam and gas and remain for a long period of time and have diverse effects on the environment. The purpose of this study is determination of the concentration of VOCs such as alachlor, anthracene, benzene, bromoform, chloroform, heptachlor, isophorone, tetrachloroethylene, γ -chlordane, toluene, etc. in water matrices. The results showed that among studies conducted on VOCs, the concentration of tetrachloroethylene, m,p-xylene, and toluene were at the top in water matrices, and the lowest average concentrations were found in chloroform, anthracene, and butyl benzyl phthalate. In terms of VOC concentrations in water matrices, China was the most polluted country. Moreover, the data analysis indicated that China was the only country with carcinogenic risk. A Monte-Carlo simulation showed that although the averages obtained were comparable to the acceptable limits, for heptachlor, the maximum carcinogenic risk is achieved at a level that is slightly over the limit, only 25% from the population being exposed.

Catalytic dye degradation by novel phytofabricated silver/zinc oxide composites

Phytofabrication of the nanoparticles with exotic shape and size is an attractive area where nanostructures with noteworthy physicochemical and optoelectronic properties that can be significantly employed for photocatalytic dye degradation. In this study a medicinal plant, Plumbago auriculata leaf extract (PALE) was used to synthesize zinc oxide particles (ZnOPs) and silver mixed zinc oxide particles (ZnOAg1Ps, ZnOAg10Ps, ZnO10Ag1Ps) by varying the concentration of the metal precursor salts, i.e. zinc acetate and silver nitrate. The PALE showed significantly high concentrations of polyphenols, flavonoids, reducing sugar, starch, citric acid and plumbagin up to 314.3 ± 0.33, 960.0 ± 2.88, 121.3 ± 4.60, 150.3 ± 3.17, 109.4 ± 2.36, and 260.4 ± 8.90 μg/ml, respectively which might play an important role for green synthesis and capping of the phytogenic nanoparticles. The resulting particles were polydispersed which were mostly irregular, spherical, hexagonal and rod like in shape. The pristine ZnOPs exhibited a UV absorption band at 352 nm which shifted around 370 in the Ag mixed ZnOPs with concomitant appearance of peaks at 560 and 635 nm in ZnO10Ag1Ps and ZnOAg1Ps, respectively. The majority of the ZnOPs, ZnOAg1Ps, ZnOAg10Ps, and ZnO10Ag1Ps were 407, 98, 231, and 90 nm in size, respectively. Energy dispersive spectra confirmed the elemental composition of the particles while Fourier transform infrared spectra showed the involvement of the peptide and methyl functional groups in the synthesis and capping of the particles. The composites exhibited superior photocatalytic degradation of methylene blue dye, maximum being 95.7% by the ZnOAg10Ps with a rate constant of 0.0463 s−1 following a first order kinetic model. The present result clearly highlights that Ag mixed ZnOPs synthesized using Plumbago auriculata leaf extract (PALE) can play a critical role in removal of hazardous dyes from effluents of textile and dye industries. Further expanding the application of these phytofabricated composites will promote a significant complementary and alternative strategy for treating refractory pollutants from wastewater.

Uncovering the Role of Surface-Attached Ag Nanoparticles in Photodegradation Improvement of Rhodamine B by ZnO-Ag Nanorods

ZnO nanorods decorated with metal nanoparticles have sparked considerable interest in recent years thanks to their suitability for a wide range of applications, such as photocatalysis, photovoltaics, antibacterial activity, and sensing devices. In this study, we prepared and investigated the improved solar-light-assisted photocatalytic activity of ZnO nanorods (NRs) decorated with Ag nanoparticles (NPs) using a conventional rhodamine B (RB) dye as a model water pollutant. We showed that the presence of Ag NPs on the surface of ZnO NRs significantly increases the degradation rate of RB dye (~0.2432 min^-1) when compared to bare ZnO NRs (~0.0431 min^-1). The improved photocatalytic activity of ZnO-Ag was further experimentally tested using radical scavengers. The obtained results reveal that ˙OH and ˙O₂^- radicals are main active species involved in the RB dye photodegradation by ZnO-Ag NRs. It was concluded that efficient charge separation plays a major role in photocatalytic activity improvement.

Ag Nanoparticles Decorated ZnO Nanorods as Multifunctional SERS Substrates for Ultrasensitive Detection and Catalytic Degradation of Rhodamine B

Industrial wastewater containing large amounts of organic pollutants is a severe threat to the environment and human health. Thus, the rapid detection and removal of these pollutants from wastewater are essential to protect public health and the ecological environment. In this study, a multifunctional and reusable surface-enhanced Raman scattering (SERS) substrate by growing Ag nanoparticles (NPs) on ZnO nanorods (NRs) was produced for detecting and degrading Rhodamine B (RhB) dye. The ZnO/Ag substrate exhibited excellent sensitivity, and the limit of detection (LOD) for RhB was as low as 10⁻¹¹ M. Furthermore, the SERS substrate could efficiently degrade RhB, with a degradation efficiency of nearly 100% within 150 min. Moreover, it retained good SERS activity after multiple repeated uses. The interaction between Ag NPs, ZnO, and RhB was further investigated, and the mechanism of SERS and photocatalysis was proposed. The as-prepared ZnO/Ag composite structure could be highly applicable as a multifunctional SERS substrate for the rapid detection and photocatalytic degradation of trace amounts of organic pollutants in water.

A zero-dimensional/two-dimensional Ag-Ag2S-CdS plasmonic nanohybrid for rapid photodegradation of organic pollutant by solar light

Herein, the two synthesis strategies are employed for rational design of 0D/2DAg-Ag₂S-CdS heterojunctions towards photocatalytic degradation of methyl orange (MO) under simulated solar light. As the first strategy, a ternary Ag-Ag₂S-CdS nanosheet (NS) heterojunction was fabricated via combined cation exchange and photo-reduction (CEPR) method (Ag-Ag₂S-CdS/CEPR). The second strategy employed coprecipitation (CP) method (Ag-Ag₂S-CdS/CP). Strikingly, SEM, TEM and HR-TEM images are manifested the first strategy is beneficial for retaining the original thickness (20.2 nm) of CdS NSs with a dominant formation of metallic Ag, whereas the second strategy increases the thickness (33.4 nm) of CdS NSs with a dominant formation of Ag₂S. The Ag-Ag₂S-CdS/CEPR exhibited 1.8-fold and 3.5-fold enhancement in photocatalytic activities as compared to those of Ag-Ag₂S-CdS/CP and bare CdS NSs, respectively. This enhanced photocatalytic activity could be ascribed to fact that the first strategy produces a high-quality interface with intimate contact between the Ag-Ag₂S-CdS heterojunctions, resulting in enhanced separation of photo-excited charge carriers, extended light absorption, and enriched active-sites. Furthermore, the degradation efficiency of Ag-Ag₂S-CdS/CEPR was significantly reduced to ∼5% in the presence of BQ (•O₂^- scavenger), indicating that •O₂^- is the major active species that can decompose MO dye under simulated solar light.

Photodegradation of Pharmaceutical Pollutants: New Photocatalytic Systems Based on 3D Printed Scaffold-Supported Ag/TiO2 Nanocomposite

Due to the release of active pharmaceutical compounds in wastewater and their persistence in the environment, dangerous consequences can develop in the aquatic and terrestrial organisms. Chitosan/Ag/TiO2 3D printed scaffolds, at different Ag nanoparticle concentrations (10, 100, 1000 ppm) are investigated here as promising materials for photocatalytic degradation under the UV–Vis irradiation of pharmaceutical compounds in wastewater. As target drugs, amoxicillin, paracetamol and their 1:1 mix were selected. Ag nanoparticles increase the photocatalytic efficiency of the system based on titanium dioxide embedded in the chitosan scaffold: in the presence of Chitosan/Ag100/TiO2, the selected pharmaceuticals (PhCs), monitored by UV–Vis spectroscopy, are completely removed in about 2 h. The photodegradation products of the PhCs were identified by Liquid Chromatography–Mass Spectroscopy and assessed for their toxicological impact on six different bacterial strains: no antibacterial activity was found towards the tested strains. This new system based on Ag/TiO2 supported on 3D chitosan scaffolds may represent an effective strategy to reduce wastewater pollution by emerging contaminants.

Experimental and computational investigation of a green Knoevenagel condensation catalyzed by zeolitic imidazolate framework-8

ZIF-8 is a highly porous, stable, and abundant surface area material that can be used as an environmentally friendly catalyst for Knoevenagel condensations. The effects of the ratio of the reactants (benzaldehyde (BA):ethyl cyanoacetate (ECA)), reaction temperature, and catalyst concentration were systematically investigated using a ZIF-8 catalyst and water as the solvent. ZIF-8 (3-5 wt%) showed excellent catalytic performance with an almost complete conversion of BA in less than 6 h with a BA:ECA molar ratio of 1:2 at different temperatures. At 60 °C, the BA conversion rate and product selectivity of the reaction reached their highest values after 4 h with a BA:ECA molar ratio of 1:1. When employing 5.0 wt% ZIF-8, almost complete BA conversion was achieved after 3 h at room temperature. ZIF-8 also demonstrated good recyclability with almost no change in its catalytic activity over five cycles. The proposed reaction mechanism is based on the catalytic activity of the basic N sites on the surface of ZIF-8, and is supported by density functional theory calculations. The present approach provides a promising strategy for the construction of simple and environmentally friendly ZIF-8 catalysts.

Flexible and high-sensitivity sensor based on Ti3C2-MoS2 MXene composite for the detection of toxic gases

It is vital to have high sensitivity in gas sensors to allow the exact detection of dangerous gases in the air and at room temperature. In this study, we used 2D MXenes and MoS₂ materials to create a Ti₃C₂-MoS₂ composite with high metallic conductivity and a wholly functionalized surface for a significant signal. At room temperature, the Ti₃C₂-MoS₂ composite demonstrated clear signals, cyclic response curves to NO₂ gas, and gas concentration-dependent. The sensitivities of the standard Ti₃C₂-MoS₂ (TM_2) composite (20 wt% MoS₂) rose dramatically to 35.8%, 63.4%, and 72.5% when increasing NO₂ concentrations to 10 ppm, 50 ppm, and 100 ppm, respectively. In addition, the composite showed reaction signals to additional hazardous gases, such as ammonia and methane. Our findings suggest that highly functionalized metallic sensing channels could be used to construct multigas-detecting sensors that are very sensitive in air and at room temperature.

Synthesis, characterization of novel ZnO/CuO nanoparticles, and the applications in photocatalytic performance for rhodamine B dye degradation

Photocatalytic deg radation of environmental pollutants is being up to date for the treatment of contaminated water. In the present study, ZnO/CuO nanomaterials were successfully fabricated by a simple sol-gel method and investigate the photo-degradation of rhodamine B (RhB). The synthesized ZnO/CuO nanoparticles were characterized by X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (UV-Vis-DRS), thermal analysis (TGA), surface charge, and Fourier transform infrared spectroscopy (FTIR). The photo-degradation of the dye RhB was followed spectroscopically. The overall composition of ZnO/CuO material was found to be wurtzite phase, with particle size of 30 nm, and the Vis light absorption increased with an increase of Cu content. The ZnO/CuO nanomaterials were highly active leading to a photo-degradation of 10 ppm RhB reaching 98% within 180 min at 0.1 g/L catalyst dosage. The change in surface charge after degradation evaluated by ζ potential measurements and the differences in functional vibration group monitored by Fourier transform infrared spectroscopy (FTIR) indicates that the RhB adsorption on the Zn45Cu surface was insignificant. And scavenging experiments demonstrate that the RhB degradation by ZnO/CuO nanomaterials involves to some degree hydroxyl radicals.

One-step fabrication and photocatalytic performance of sea urchin-like CuO/ZnO heterostructures

Sea urchin-like hierarchical p-CuO/n-ZnO heterostructures were fabricated through one-step chemical bath deposition method without any surfactant or heat treatment. The morphologies and crystal structures of the obtained CuO/ZnO heterostructures were...

Facile and Green Synthesis of Silver Quantum Dots Immobilized onto a Polymeric CTS-PEO Blend for the Photocatalytic Degradation of p-Nitrophenol

Immobilization of inorganic metal quantum dots (especially, noble transition metals) onto organic polymers to synthesize nanometal-polymer composites (NMPCs) has attracted considerable attention because of their advanced optical, electrical, catalytic/photocatalytic, and biological properties. Herein, novel, highly efficient, stable, and visible light-active NMPC photocatalysts consisting of silver quantum dots (Ag QDs) immobilized onto polymeric chitosan-polyethylene oxide (CTS-PEO) blend sheets have been successfully prepared by an in situ self-assembly facile casting method as a facile and green approach. The CTS-PEO blend polymer acts as a reducing and a stabilizing agent for Ag QDs which does not generate any environmental chemical pollutant. The prepared x wt % Ag QDs/CTS-PEO composites were fully characterized through X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis, and UV/visible spectroscopy. The characterization results indicated the successful synthesis of the Ag QDs/CTS-PEO composites by the interactions and complexation between x wt % Ag QDs and CTS-PEO blend sheets. TEM images revealed small granules randomly distributed onto the CTS-PEO blend sheets, indicating the immobilization of Ag QDs onto CTS-PEO composites. The presence of a surface plasmon resonance (SPR) band and the shifting of the absorption edge toward higher wavelengths in the UV/vis spectra indicated the formation of x wt % Ag QDs/CTS-PEO composites. The Ag QDs in the polymeric blend matrix led to remarkable enhancement in the optical, thermal, electrical, and photocatalytic properties of x wt % Ag QDs/CTS-PEO composites. The photocatalytic efficiency of the prepared composites was evaluated by the photodegradation of p-nitrophenol (PNP) under simulated sunlight. The maximum photocatalytic degradation reached 91.1% efficiency within 3 h for the 12.0 wt % Ag QDs/CTS-PEO photocatalyst. Generally, the Ag QDs immobilized onto CTS-PEO blend composites significantly enhance the SPR effect and the synergistic effect and reduce the band gap, leading to a high photocatalytic activity.

Sunlight-induced photocatalytic degradation of organic pollutants by biosynthesized hetrometallic oxides nanoparticles

Dyes and phenols are extensively used chemicals in petrochemicals, pharmaceuticals, textile, and paints industries. Due to high persistence, bioaccumulation, and toxicity, their removal from the environment is highly imperative by advanced techniques. Single metal oxide nanomaterials are generally associated with limitations of large bandgap (> 3eV) and charge recombination. Therefore, heterometallic oxides (HMOs) as CuFe₂O₄, CuMn₂O₄, and MnZn₂O₄ have been synthesized via green route by employing leaf extract of Azadirachta indica. XRD revealed the crystalline nature of HMOs nanospheres with particle size less than 100 nm. Subsequently, HMOs nanocatalysts were used as photocatalyst for removal of 3-amino phenols (3-AP) and eriochrome black T (EBT) from water under sunlight. Reaction parameters namely pollutant concentration (50-130 mgL^-1), catalyst dose (20-100 mg), and pH (3-11) were optimized in order to get best results. Substantial degradation (80-95%) of pollutants (50 mgL^-1) by HMOs (80 mg) was achieved at neutral pH under sunlight exposure. Highest removal by CuFe₂O₄ might be due to its high surface area (35.7 m²g^-1), low band gap (2.4 eV), larger particle stability (Zeta potential: -22.0 mV), and lower photoluminescence intensity. Sharp declines in curves were visually confirmed by color change and indicated for first-order kinetics of degradation with initial Langmuir adsorption. Spectrophotometric analysis revealed that half-life (t_1/2) of 3-AP (0.9-1.7 h) and EBT (0.6-0.8 h) were significantly reduced. Faster degradation of EBT than 3-AP was because of less electronegative N-atom at the diazo group. Scavenger analysis indicated the presence of active radicals in photo-catalytic degradation of 3-AP and EBT. All HMOs have shown high reusability (n=8) which ensures their stability, sustainability, and efficiency. Overall, green synthesized HMOs nanoparticles with prominent surface characteristics offer a viable alternative photocatalyst for industrial applications.

Novel organic assisted Ag-ZnO photocatalyst for atenolol and acetaminophen photocatalytic degradation under visible radiation: performance and reaction mechanism

This study is on photocatalytic degradation of pharmaceutical residues of atenolol (ATL) and acetaminophen (ACT) present in secondary effluent under visible light irradiation stimulated by Ag doped ZnO (Ag-ZnO) photocatalyst. Lawsonia inermis leaf extract was used for reduction of Zinc sulphate to ZnO nanoparticles (NPs). Further, ZnO NPs were doped with Ag and characterized by XRD, FT-IR, SEM-EDX, surface area analyzer, UV-Vis, and photoluminescence spectrometry to analyze the structure, morphology, chemical composition, and optical property. FT-IR analysis revealed major functional groups such as OH, C=O, and SEM analysis depicted the polyhedron shape of the NPs with size range of 100 nm. Ag-ZnO NPs were used in the photocatalytic degradation of ATL and ACT, and its removal was evaluated by varying initial contaminant concentration, catalyst dosage, and initial pH. Findings indicate that Ag-ZnO NPs demonstrated relative narrow bandgap and efficient charge separation that resulted in enhanced photocatalytic activity under visible light illumination. The photocatalytic degradation of ATL and ACT fitted well with pseudo-first-order kinetic model. Further, it was found that under optimal conditions of 5 mg/L of contaminants, pH of 8.5, and catalyst dose of 1 g/L, degradation efficiency of 70.2% (ATL) and 90.8% (ACT) was achieved for a reaction time of 120 min. More than 60% reduction in TOC was observed for both contaminants and OH• pathway was found to be the major removal process. Ag-ZnO photocatalyst showed good recycling performance, and these findings indicate that it could be cost effectively employed for removing emerging contaminants under visible light radiation.

Recent Progress on Metal-Enhanced Photocatalysis: A Review on the Mechanism

Metal-enhanced photocatalysis has recently received increasing interest, mainly due to the ability of metal to directly or indirectly degrade pollutants. In this review, we briefly review the recent breakthroughs in metal-enhanced photocatalysis. We discussed the recent progress of surface plasmon resonance (SPR) effect and small size effect of metal nanoparticles on photocatalysis; in particular, we focus on elucidating the mechanism of energy transfer and hot electron injection/transfer effect of metal nanoparticles and clusters while as photocatalysts or as cophotocatalysts. Finally, we discuss the potential applications of metal-enhanced photocatalysis, and we also offer some perspectives for further investigations.

Cellulose Paper Modified by a Zinc Oxide Nanosheet Using a ZnCl2-Urea Eutectic Solvent for Novel Applications

Cellulose paper has been functionalized by nanoparticles such as Ag nanoparticles, TiO2, and BaTiO3 for versatile applications including supercapacitor, sensors, photoactivity, and packaging. Herein, zinc oxide (ZnO) nanosheet-modified paper (ZnO@paper) with excellent antibacterial properties was fabricated via a mild ZnCl2-urea eutectic solvent. In this proposed method, cellulose fibers as the raw material for ZnO@paper were treated by an aqueous solvent of ZnCl2-urea; the crystalline region was destroyed and [ZnCl]+-based cations were adsorbed on the surface of cellulose fibers, facilitating more ZnO growth on ZnO@paper. A flexible paper-based triboelectric nanogenerator (P-TENG) was made of ZnO@paper paired with a PTFE film. The P-TENG presents high triboelectric output performance and antibacterial activity. For instance, the output voltage and current of the P-TENG were 77 V and 0.17 μA, respectively. ZnO@paper showed excellent antibacterial activity against E. coli and S. aureus, suggesting that a P-TENG can restrain and kill the bacteria during the working process. The results also indicated that ZnO could improve the surface roughness of cellulose paper, enhancing the output performance of a flexible P-TENG. In addition, the potential application of a P-TENG-based pressure sensor for determining human motion information was also reported. This study not only produced a high-performance P-TENG for fabricating green and sustainable electronics, but also provides an effective and novel method for ZnO@paper preparation.

Insight into the degradation of p-nitrophenol by visible-light-induced activation of peroxymonosulfate over Ag/ZnO heterojunction

In this report, the peroxymonosulfate activation over Ag/ZnO heterojunction under visible light (Ag/ZnO/PMS/Vis) for p-nitrophenol (p-NP) contaminant degradation was conducted in detail. Herein, the catalyst dosage was decreased, and the results showed that a dosage of 0.5 g L^-1 Ag/ZnO and 4 mM PMS almost completely degraded 30 mg L^-1 p-NP after 90 min of irradiation. In addition, the PMS activation mechanism of Ag/ZnO/PMS/Vis system was proposed by investigations of the influence of PMS concentration, the FTIR spectra, UV-Vis spectroscopy, and electrochemical analyses. Additionally, the role of SO₄^•- in the photocatalytic reaction is determined by a combination of a trapping test using isopropanol and tert-butanol as probe compounds and electron spin resonance (ESR) spectroscopy. This report provides a potential alternative to remove persistent organic contaminants in sewage using PMS incorporated with Ag/ZnO under visible light irradiation.

High-efficient reduction of methylene blue and 4-nitrophenol by silver nanoparticles embedded in magnetic graphene oxide

In this study, a ternary magnetically separable nanocomposite of silver nanoparticles (AgNPs) embedded in magnetic graphene oxide (Ag/Fe₃O₄@GO) was designed and synthesized. Beta-cyclodextrin was used as a green reducing and capping agent for decorating of AgNPs on Fe₃O₄@GO. The fabricated material was characterized using X-ray diffractometry, Fourier transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometry, and energy-dispersive X-ray spectroscopy. The catalytic properties of the prepared Ag/Fe₃O₄@GO for the reduction of 4-nitrophenol (4-NP) and methylene blue (MB) dye with sodium borohydride were investigated in detail. The morphological and structural studies revealed that Fe₃O₄ and AgNPs with a mean size of 12 nm were uniformly distributed on the GO sheet at high densities. The catalytic tests showed that Ag/Fe₃O₄@GO exhibited an ultrafast catalytic reduction of 4-NP and MB with a reduction rate constant of 0.304 min^-1 and 0.448 min^-1, respectively. Moreover, the catalyst demonstrated excellent stability and reusability, as evidenced by the more than 97% removal efficiency maintained after five reuse cycles. The Ag/Fe₃O₄@GO catalyst could be easily recovered by the magnetic separation due to the superparamagnetic nature of Fe₃O₄ with high saturated magnetization (45.7 emu/g). Besides, the formation of networking between the formed AgNPs and β-CD through hydrogen bonding prevented the agglomeration of AgNPs, ensuring their high catalytic ability. The leaching study showed that the dissolution of Fe and Ag from Ag/Fe₃O₄@GO was negligible, indicating the environmental friendliness of the synthesized catalyst. Finally, the high catalytic performance, excellent stability, and recoverability of Ag/Fe₃O₄@GO make it a potential candidate for the reduction of organic pollutants in wastewater.

Ag Nanoparticle-Decorated MoS2 Nanosheets for Enhancing Electrochemical Performance in Lithium Storage

Metallic phase 1T MoS₂ is a well-known potential anode for enhancing the electrochemical performance of lithium-ion batteries owing to its mechanical/chemical stability and high conductivity. However, during the lithiation/delithiation process, MoS₂ nanosheets (NSs) tend to restack to form bulky structures that deteriorate the cycling performance of bare MoS₂ anodes. In this study, we prepared Ag nanoparticle (NP)-decorated 1T MoS₂ NSs via a liquid exfoliation method with lithium intercalation and simple reduction of AgNO₃ in NaBH₄. Ag NPs were uniformly distributed on the MoS₂ surface with the assistance of 3-mercapto propionic acid. Ag NPs with the size of a few nanometers enhanced the conductivity of the MoS₂ NS and improved the electrochemical performance of the MoS₂ anode. Specifically, the anode designated as Ag3@MoS₂ (prepared with AgNO₃ and MoS₂ in a weight ratio of 1:10) exhibited the best cycling performance and delivered a reversible specific capacity of 510 mAh·g⁻¹ (approximately 73% of the initial capacity) after 100 cycles. Moreover, the rate performance of this sample had a remarkable recovery capacity of ~100% when the current decreased from 1 to 0.1 A·g⁻¹. The results indicate that the Ag nanoparticle-decorated 1T MoS₂ can be employed as a high-rate capacity anode in lithium-ion storage applications.

pH-triggered degradation and release of doxorubicin from zeolitic imidazolate framework-8 (ZIF8) decorated with polyacrylic acid

Zeolite imidazolate framework-8 (ZIF8) represents a class of highly porous materials with a very high surface area, large pore volume, thermal stability, and biocompatibility. In this study, ZIF8-based nanostructures demonstrated a high loading capacity for doxorubicin (62 mg Dox per g ZIF8) through the combination of π-π stacking, hydrogen bonding, and electrostatic interactions. Dox-loaded ZIF8 was subsequently decorated with polyacrylic acid (PAA) (ZIF8-Dox@PAA) that showed good dispersity, fluorescent imaging capability, and pH-responsive drug release. The stable localization and association of Dox in ZIF8@PAA were investigated by C13 nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy. The NMR chemical shifts suggest the formation of hydrogen bonding interactions and π-π stacking interactions between the imidazole ring of ZIF8 and the benzene ring of Dox that can significantly improve the storage of Dox in the ZIF8 nanostructure. Additionally, the release mechanism of ZIF8-Dox@PAA was discussed based on the detachment of the PAA layer, enhanced solubility of Dox, and destruction of ZIF8 at different pH conditions. In vitro release test of ZIF8-Dox@PAA at pH 7.4 showed the low release rate of 24.7% even after 100 h. However, ZIF8-Dox@PAA at pH 4.0 exhibited four stages of release profiles, significantly enhanced release rate of 84.7% at the final release stage after 30 h. The release kinetics of ZIF8-Dox@PAA was analyzed by the sigmoidal Hill, exponential Weibull, and two-stage BiDoseResp models. The ZIF8-Dox@PAA nanocarrier demonstrated a promising theranostic nanoplatform equipped with fluorescent bioimaging, pH-responsive controlled drug release, and high drug loading capacity.

Hexylresorcinol calix[4]arene-assisted synthesis of ZnO–Au micro–nano materials with enhanced photodegradation performance to degrade harmful organic compounds

HRCA not only acts as a reducing agent, but also plays a role in morphology regulation in the synthesis of ZnO–Au micro–nano materials. Gold particles deposited on the formed ZnO sheets and prevented the sheet-like ZnO from accumulating.

Recent Progress on Metal-Enhanced Photocatalysis: A Review on the Mechanism

Metal-enhanced photocatalysis has recently received increasing interest, mainly due to the ability of metal to directly or indirectly degrade pollutants. In this review, we briefly review the recent breakthroughs in metal-enhanced photocatalysis. We discussed the recent progress of surface plasmon resonance (SPR) effect and small size effect of metal nanoparticles on photocatalysis; in particular, we focus on elucidating the mechanism of energy transfer and hot electron injection/transfer effect of metal nanoparticles and clusters while as photocatalysts or as cophotocatalysts. Finally, we discuss the potential applications of metal-enhanced photocatalysis, and we also offer some perspectives for further investigations.