An investigation into the hybrid architecture of Mn-Co nanoferrites incorporated into a polyaniline matrix for photoresponse studies

In this study, an enhanced photoresponse was observed in the Mn-Co Nanoferrites (MCFs)-Polyaniline (PANI) nanohybrid architecture due to the formation of interface between PANI and MCFs, which provided a conduction pathway for the movement of charge carriers, and these interfaces were observed in a high-resolution transmission electron micrograph (HR-TEM). X-ray photoelectron spectroscopy (XPS) suggests that the carbon (C 1s) of the MCF-PANI nanohybrid shows peaks at 287.80 eV for CO, 286.17 eV for C-O, 285.24 eV for C-N, 284.50 eV for the sp3 hybridized carbon (C-C/C-H) and 283.84 eV for the sp2 hybridized carbon (CC). Current-voltage (I-V) curves reveal an ohmic nature of the MCF-PANI nanohybrid photodetector device. The photoresponse measurements were analyzed using the trap depth concept, demonstrating that the conductive polymer increases the photoconduction mechanism efficiency of MCFs. The constructed photodetector device exhibits a high photoresponsivity of 22.69 A W-1, a remarkable detectivity of 1.36 × 1012 cm Hz1/2 W-1 and a fast rise/decay time of 0.7/0.8 s. The excellent performance of the as-fabricated photodetector device could be explained by the intimate interaction between MCFs and PANI at their interface.

An Insight into Carbon Nanomaterial-Based Photocatalytic Water Splitting for Green Hydrogen Production

At present, the energy shortage and environmental pollution are the burning global issues. For centuries, fossil fuels have been used to meet worldwide energy demand. However, thousands of tons of greenhouse gases are released into the atmosphere when fossil fuels are burned, contributing to global warming. Therefore, green energy must replace fossil fuels, and hydrogen is a prime choice. Photocatalytic water splitting (PWS) under solar irradiation could address energy and environmental problems. In the past decade, solar photocatalysts have been used to manufacture sustainable fuels. Scientists are working to synthesize a reliable, affordable, and light-efficient photocatalyst. Developing efficient photocatalysts for water redox reactions in suspension is a key to solar energy conversion. Semiconductor nanoparticles can be used as photocatalysts to accelerate redox reactions to generate chemical fuel or electricity. Carbon materials are substantial photocatalysts for total WS under solar irradiation due to their high activity, high stability, low cost, easy production, and structural diversity. Carbon-based materials such as graphene, graphene oxide, graphitic carbon nitride, fullerenes, carbon nanotubes, and carbon quantum dots can be used as semiconductors, photosensitizers, cocatalysts, and support materials. This review comprehensively explains how carbon-based composite materials function as photocatalytic semiconductors for hydrogen production, the water-splitting mechanism, and the chemistry of redox reactions. Also, how heteroatom doping, defects and surface functionalities, etc., can influence the efficiency of carbon photocatalysts in H2 production. The challenges faced in the PWS process and future prospects are briefly discussed.

Efficient Removal of Inorganic and Organic Pollutants over a NiCo2O4@MOF-801@MIL88A Photocatalyst: The Significance of Ternary Heterojunction Engineering

Energy problems are a substantial concern in a global society that can be solved by replacing with sustainable energies. In recent years, designing nanomaterials as photocatalysts that can produce chemical energy with the utilization of infinite visible light energy became a new solution for water treatment. In the present study, NiCo₂O₄@MOF-801 has been synthesized with multiple properties, and then, a novel three-layer NiCo₂O₄@MOF-801@MIL88A photocatalyst has been successfully synthesized to improve meropenem degradation and Cr(VI) reduction. The prepared photocatalyst was characterized by XRD, IR, XPS, TEM, SEM, TGA, BET, EIS, PL, and UV-vis. According to the structural and optical analysis performed, the interaction between the components formed a heterojunction structure that prevented the recombination of charge carriers and increased the photocatalytic performance. Photocatalytic simulation tests also proved the reduction of chromium and degradation of antibiotics to find the optimal heterogeneous performance. As a result, the NiCo₂O₄@MOF-801@MIL88A composite can completely reduce Cr(VI) in 45 min, which is strongly preferable to any pure component's performance. Overall, this work offers a low-cost but high-efficiency material that can remove organic and inorganic contaminants from water.

Advances in Hybrid Composites for Photocatalytic Applications: A Review

Heterogeneous photocatalysts have garnered extensive attention as a sustainable way for environmental remediation and energy storage process. Water splitting, solar energy conversion, and pollutant degradation are examples of nowadays applications where semiconductor-based photocatalysts represent a potentially disruptive technology. The exploitation of solar radiation for photocatalysis could generate a strong impact by decreasing the energy demand and simultaneously mitigating the impact of anthropogenic pollutants. However, most of the actual photocatalysts work only on energy radiation in the Near-UV region (<400 nm), and the studies and development of new photocatalysts with high efficiency in the visible range of the spectrum are required. In this regard, hybrid organic/inorganic photocatalysts have emerged as highly potential materials to drastically improve visible photocatalytic efficiency. In this review, we will analyze the state-of-art and the developments of hybrid photocatalysts for energy storage and energy conversion process as well as their application in pollutant degradation and water treatments.

Oxygen Vacancy-Mediated Z-Scheme Charge Transfer in a 2D/1D B-Doped g-C3N4/rGO/TiO2 Heterojunction Visible Light-Driven Photocatalyst for Simultaneous/Efficient Oxygen Reduction Reaction and Alcohol Oxidation

Hydrogen peroxide (H₂O₂) is a powerful oxidant that directly or indirectly oxidizes many organic and inorganic contaminants. The photocatalytic generation of H₂O₂ is achieved by using a semiconductor photocatalyst in the presence of alcohol as a proton source. Herein, we have synthesized oxygen vacancy (O_v)-mediated TiO₂/B-doped g-C₃N₄/rGO (TBCN@rGO) ternary heterostructures by a simple hydrothermal technique. Several characterization techniques were employed to explore the existence of oxygen vacancies in the crystal structure and investigate their impact on the optoelectronic properties of the catalyst. Oxygen vacancies offered additional sites for adsorbing molecular oxygen, activating alcohols, and facilitating electron migration from TBCN@rGO to the surface-adsorbed O₂. The defect creation (oxygen vacancy) and Z-scheme mechanistic pathways create a suitable platform for generating H₂O₂ by two-electron reduction processes. The optimized catalyst showed the highest photocatalytic H₂O₂ evolution rate of 172 μmol/h, which is 1.9 and 2.5 times greater than that of TBCN and BCN, respectively. The photocatalytic oxidation of various lignocellulose-derived alcohols (such as furfural alcohol and vanillyl alcohol) and benzyl alcohol was also achieved. Photocatalytic activity data, physicochemical and optoelectronic features, and trapping experiments were conducted to elucidate the structure-activity relationships. The TBCN@rGO acts as a multifunctional Z-scheme photocatalyst having an oxygen vacancy, modulates surface acidity-basicity required for the adsorption and activation of the reactant molecules, and displays excellent photocatalytic performance due to the formation of a large number of active surface sites, increased electrical conductivity, improved charge transfer properties, outstanding photostability, and reusability. The present study establishes a unique strategy for improving H₂O₂ generation and alcohol oxidation activity and also provides insights into the significance of a surface vacancy in the semiconductor photocatalyst.

Earth-abundant and environmentally benign Ni-Zn iron oxide intercalated in a polyaniline based nanohybrid as an ultrafast photodetector

Nickel-zinc iron oxide (NZF) was introduced into a polyaniline (PANI) matrix by an in situ chemical oxidation polymerization approach. The surface composition and chemical states were investigated by X-ray photoelectron spectroscopy (XPS), which revealed an Fe 2p spectrum with the two peak positions of Fe 2p_3/2 and Fe 2p_1/2 at 711.00 and 724.48 eV, respectively. Deconvolution of the Fe 2p_3/2 peak revealed two components with binding energies of 713.98 and 718.16 eV, corresponding to the presence of Fe cations in the octahedral and tetrahedral sites. Additionally, the Rietveld refinement of NZF showed a cubic system with the Fd₃m space group. High-resolution transmission electron microscopy (HRTEM) analysis showed that the NZF material strongly interacts with polyaniline, while the selected area electron diffraction (SAED) pattern perfectly matched with the XRD data. Lognormal distribution was used to determine the particle size, which was found to be in the range of 1-100 nm. A flexible photodetector device utilizing the NZF-PANI nanohybrid was fabricated on an environmentally friendly, biodegradable cellulose paper substrate and the device exhibited excellent performance, i.e., a responsivity of 0.069 A W^-1 and detectivity of 7.258 × 10¹⁰ Jones at a very low voltage of 0.1 V. The non-stretched device showed a responsivity of 24.980 A W^-1 at 5 V, whereas at 2 cm^-1 bending curvature, the device showed a responsivity of 20.175 A W^-1, which was much higher than the responsivity of a commercial photodetector (<0.5 A W^-1).

New bidental sulfur-doped graphene quantum dots modified with gold as a catalyst for hydrogen generation

Disadvantages of fossil fuels encourage researchers to develop clean combustion sources, in particular, H₂ due to the high potential energy and safe by-products. Herein, Au was deposited on S-doped graphene quantum dots to obtain a heterogeneous photocatalyst for the degradation of formic acid toward H₂ generation. Insertion of thiol groups on graphene quantum dots was carried out by self-condensation reaction of citric acid in the presence of Dimaval, as the thiol groups carrier. After the complexation of Au with the prepared S-doped graphene quantum dots, the catalytic activity of composite was evaluated in formic acid degradation to generate H₂ under visible light. Au@S-doped graphene quantum dots demonstrated superior catalytic activity with the turnover frequency up to 112 h^-1. The reaction enjoys significant benefits such as stability and recyclability of the catalyst, excellent reaction rate, and mild reaction conditions.

Impact of piezoelectric effect on the heterogeneous visible photocatalysis of g-C3N4/Ag/ZnO tricomponent

In recent years, the piezophotocatalytic mechanism had been intensively recognized as a potential and promising route to sewage treatment. Here we report the piezoelectric effect improved heterogeneous photocatalysis of g-C₃N₄/Ag/ZnO (g-CN/A/Z) tricomponent in rhodomine B (RhB) degradation. Initially, the nanomaterials were characterized for their physico-chemical and optoelectronic properties using analytical techniques such as x-ray diffraction (XRD), scanning & transmission electron microscopes (SEM & TEM), UV-vis spectrophotometer and photoluminescence spectroscopy (PL). In addition, the photoelectrochemical activity of determining the photocurrent density and electrochemical impendence response were also been conducted. The catalytic properties of the tricomponent, g-CN/A/Z was studied with the degradation of RhB with visible photons irradiation and ultrasonication. In piezophotocatalysis, degradation up to 89% of RhB was achieved with 1.26 folds synergetic effect on par to the photocatalysis and piezocatalysis.

Spinel ferrites (MFe2O4): Synthesis, improvement and catalytic application in environment and energy field

To develop efficient catalysts is one of the major ways to solve the energy and environmental problems. Spinel ferrites, with the general chemical formula of MFe₂O₄ (where M = Mg²⁺, Co²⁺, Ni²⁺, Zn²⁺, Fe²⁺, Mn²⁺, etc.), have attracted considerable attention in catalytic research. The flexible position and valence variability of metal cations endow spinel ferrites with diverse physicochemical properties, such as abundant surface active sites, high catalytic activity and easy to be modified. Meanwhile, their unique advantages in regenerating and recycling on account of the magnetic performances facilitate their practical application potential. Herein, the conventional as well as green chemistry synthesis of spinel ferrites is reviewed. Most importantly, the critical pathways to improve the catalytic performance are discussed in detail, mainly covering selective doping, site substitution, structure reversal, defect introduction and coupled composites. Furthermore, the catalytic applications of spinel ferrites and their derivative composites are exclusively reviewed, including Fenton-type catalysis, photocatalysis, electrocatalysis and photoelectro-chemical catalysis. In addition, some vital remarks, including toxicity, recovery and reuse, are also covered. Future applications of spinel ferrites are envisioned focusing on environmental and energy issues, which will be pushed by the development of precise synthesis, skilled modification and advanced characterization along with emerging theoretical calculation.

Developing Iron-Nickel Bimetallic Oxides with Nanocage Structures As High-Performance Bifunctional Catalysts via the Ensemble Effect from Nitrogen Sources

Metal-air batteries will serve as renewable and ecofriendly energy-storage systems in the future because of their high theoretical energy-density performance and unlimited resources, using oxygen as fuel materials compared with commercial lithium-ion batteries. However, the unsuitable inactive reactions at the air-electrode interface (the oxygen reduction reaction and the oxygen evolution reaction) in the metal-air battery are major challenges. In this study, we report nitrogen (N)-doped iron (Fe) and nickel (Ni) bimetallic catalysts with a hollow structure (Fe-Ni nanocage) as outstanding bifunctional catalysts, which have not been reported previously. The open structure in the catalysts simultaneously has an active inner cavity and an outer shell; catalysts have a high active surface area, resulting in remarkable electrochemical performance. Furthermore, the electron transfer phenomenon due to the "ensemble effect" generates a higher catalyst activation. Nitrogen has a higher electronegativity than the metal cations, so doped nitrogen sources draw the electron into iron and nickel cations, and the deprived oxidation state of the metal cations accelerates the electrocatalytic performance.

Au decorated BiVO4 inverse opal for efficient visible light driven water oxidation

Photocatalytic water splitting provides an effective way to prepare hydrogen and oxygen. However, the weak light utilization and sluggish kinetics in the oxygen evolution reaction (OER) process substantially retard the photocatalytic efficiency. In this context, modification of the semiconductors to overcome these limits has been the effective strategy for obtaining highly-efficient photocatalytic water oxidation. Here, plasmonic Au has been loaded onto BiVO4 inverse opal (IO) for photocatalytic water oxidation. It is discovered that the IO structure provides higher specific surface area and favors light absorption on BiVO4. In the meantime, the plasmonic Au can simultaneously enhance the light-utilization capability and photogenerated charge carrier utilization ability of the BiVO4 IO. As a result, a high photocurrent density and long photogenerated charge carrier lifetime can be achieved on the optimized Au-BiVO4 IO, thereby obtaining a superior photocatalytic activity with an oxygen production rate of 9.56 μmol g-1 h-1.

Generation of Hydrogen Gas Using CuCr2O4-g-C3N4 Nanocomposites under Illumination by Visible Light

In this research, nanocomposites made of CuCr₂O₄-g-C₃N₄ accommodating distinct contents of CuCr₂O₄ (1-4 wt %) nanoparticles (NPs) were endorsed for hydrogen gas production after illumination by visible light in the presence of aqueous glycerol solution. The ultrasonication-mixture method was applied to assure the homogeneous distribution of CuCr₂O₄ NPs over synthesized mesoporous g-C₃N₄. Such nanocomposites possess suppressed recombination between the photoinduced charges. High-resolution transmission electron microscopy and X-ray photoelectron spectroscopy examinations affirmed the formation of CuCr₂O₄-g-C₃N₄ heterojunctions. The separation between the induced charges and the photocatalytic performance with the CuCr₂O₄ NP amount were investigated. The CuCr₂O₄-g-C₃N₄ heterojunction of 3 wt % CuCr₂O₄ content was documented as the optimal heterojunction. Upgraded hydrogen gas generation was attained over the optimal heterojunction with the extent of ten and thirty times as those registered for pure CuCr₂O₄ and g-C₃N₄ specimens, respectively, under illumination by visible light. The photocatalytic performance acquired by the diverse synthesized specimens was assessed not only by their effectiveness to absorb light in the visible region but also by their potential to separate the photoinduced charges.

Plasmonic ZnO/Au/g-C3N4 nanocomposites as solar light active photocatalysts for degradation of organic contaminants in wastewater

In the present study, novel ZnO/Au/graphitic carbon nitride (g-C₃N₄) nanocomposites were fabricated via a facile and eco-friendly liquid phase pulsed laser process followed by calcination. Notably, the approach did not necessitate the use of any capping agents or surfactants. The as-prepared photocatalysts were evaluated by various electron microscopy and spectroscopy techniques. The obtained results confirmed good dispersion of the Au nanoparticles (NPs) on the surface of spherical ZnO particles deposited on the g-C₃N₄ nanosheets. The ZnO/Au/g-C₃N₄ nanocomposite exhibited substantially enhanced catalytic activity toward the degradation of methylene blue (MB) under simulated solar light irradiation. In particular, the ZnO/Au15/g-C₃N₄ composite containing 15 wt% Au displayed a rate constant, which was approximately 3 and 5 times greater than those of pristine g-C₃N₄ and ZnO, respectively. This improved photocatalytic activity of ZnO/Au15/g-C₃N₄ was attributed to the surface plasmon resonance of Au NPs and the synergistic effects between ZnO and g-C₃N₄. The boundary between ZnO/Au and g-C₃N₄ enabled direct migration of the photogenerated electrons from g-C₃N₄ to ZnO/Au, which hindered the recombination of electron-hole pairs and enhanced the carrier separation efficiency. Additionally, a plausible MB degradation mechanism over the ZnO/Au/g-C₃N₄ photocatalyst is proposed based on the results of the conducted scavenger study.

Earth abundant transition metal ferrite nanoparticles anchored ZnO nanorods as efficient and stable photoanodes for solar water splitting

Poor light absorption, severe surface charge recombination and fast degradation are the key challenges with ZnO nanostructures based electrodes for photoelectrochemical (PEC) water splitting. Here, this study attempts to design an efficient and durable nano-heterojunction photoelectrode by integrating earth abundant chemically stable transition metal spinel ferrites MFe₂O₄ (M = Co and Ni) nano-particles on ZnO Nanorod arrays. The low band gap magnetic ferrites improve the solar energy harvesting ability of the nano-heterojunction electrodes in ultraviolet-visible light region resulting in a maximum increase of 105% and 190% in photocurrent density and applied bias photon-to-current efficiency, respectively, compared to pristine ZnO nanorods. The favourable type-II band alignment at the ferrites/ZnO nano-heterojunction provides significantly enhanced photo-generated carrier separation and transfer, endowing the excellent solar H₂ evolution ability (743 and 891 μmol cm^-2 h^-1for ZnO/CoFe₂O₄ and ZnO/NiFe₂O₄, respectively) of the photoanodes by using sacrificial agent. The hybrid nanostructures deliver long term stability of the electrode against photocorrosion. This work demonstrates an easy but effective strategy to develop low-cost earth abundant ferrites-based heterojunction electrodes, which offers excellent PEC activity and stability.

An Overview on Graphene-Metal Oxide Semiconductor Nanocomposite: A Promising Platform for Visible Light Photocatalytic Activity for the Treatment of Various Pollutants in Aqueous Medium

Graphene is one of the most favorite materials for materials science research owing to its distinctive chemical and physical properties, such as superior conductivity, extremely larger specific surface area, and good mechanical/chemical stability with the flexible monolayer structure. Graphene is considered as a supreme matrix and electron arbitrator of semiconductor nanoparticles for environmental pollution remediation. The present review looks at the recent progress on the graphene-based metal oxide and ternary composites for photocatalysis application, especially for the application of the environmental remediation. The challenges and perspectives of emerging graphene-based metal oxide nanocomposites for photocatalysis are also discussed.

Conversion of a Type-II to a Z-Scheme Heterojunction by Intercalation of a 0D Electron Mediator between the Integrative NiFe2O4/g-C3N4 Composite Nanoparticles: Boosting the Radical Production for Photo-Fenton Degradation

A carbon dot (CD)-intercalated NiFe2O4 (NFO)/graphitic carbon nitride (g-C3N4, g-CN) ternary Z-scheme heterojunction was synthesized by the facile wet chemical method and used for photo-Fenton degradation. The structural, optical, electrical, vibrational, and morphological properties of the photocatalysts were investigated through various analytical methods. The CD-intercalated heterojunction formation was analyzed by high-resolution transmission electron microscopy (HRTEM). The intercalated CD acted as an electron donor/acceptor, which converted a type-II heterojunction to a Z-scheme heterojunction. The formation of Z-scheme heterojunction was confirmed by the enormous production of radicals (hydroxyl (OH•) and superoxide (O2 -)) and the elemental trapping experiment. In particular, the heterojunction photocatalyst NFO/5g-CN/7.5CD showed the highest photo-Fenton degradation efficiency of 99% for rhodamine B (Rh B) and 93% for tetracycline (TCN) in the presence of H2O2. The charge separation and electron transport behaviors of the photocatalyst were examined by photoluminescence (PL) and photocurrent measurements. In the Z-scheme photo-Fenton system, hydroxyl and superoxide radicals played a vital role in the visible-light-driven degradation process. Hence, the prepared Z-scheme ternary photocatalyst is well suitable for wastewater treatment in practical use.

A general steam-assisted method for one-step synthesis of polymeric carbon nitride nanosheets with/without doping for efficient photocatalytic hydrogen evolution

Nano-structuring of polymeric carbon nitride (PCN) is an important strategy to improve its photocatalytic performance, while facile and green methods are scarce yet. Herein, we proposed a novel steam-assisted method to prepare holey PCN nanosheets in one step. Only a green gas template, i.e. steam, decomposed from the recyclable steam source Mg(OH)2 is needed for PCN nano-structuring. Moreover, in situ element doping of nano-structured PCN can be synchronously realized via this method. The holey PCN nanosheets and doped counterparts have boosted visible-light photocatalytic H2 evolution activities 12-35 times that of bulk PCN, benefitting from enlarged specific surface area, suppressed photogenerated electron-hole recombination and prolonged charge carrier lifetime. Steam-assisting may be a useful strategy for the facile and green synthesis of other nanosized PCN materials.

Facile construction of a novel NiFe2O4@P-doped g-C3N4 nanocomposite with enhanced visible-light-driven photocatalytic activity

Construction of a Z-scheme-based photocatalyst, i.e., NiFe₂O₄@P-g-C₃N₄ nanocomposite, was successfully fabricated by coupling phosphorus-doped g-C₃N₄ with spinel structure NiFe₂O₄. The structural, morphological, and spectroscopic data of the as-synthesized photocatalyst was successfully characterized through XRD, FTIR, SEM, TEM, UV-Vis DRS, PL, and XPS techniques. It was found that NiFe₂O₄@P-g-C₃N₄ had an increased light-absorption capacity, high exciton separation, low photogenerated electron-hole recombination, and showed better photocatalytic activity toward phenol oxidation and hydrogen energy production than the neat materials. Photocatalytic phenol oxidation by 20 wt% NFO@P-CN was also superior and could achieve a 96% conversion, which was 2 and 3 times higher than that by P-CN and NFO, respectively. The 20 wt% NFO@P-CN showed excellent photostability and was able to evolve 904 μmol h^-1 H₂ under visible-light irradiation. The enhanced photocatalytic activity of NiFe₂O₄@P-g-C₃N₄ was in good agreement with the photocurrent results. The synergistic effect between P-CN and NFO could accelerate photogenerated charge separation and, moreover, the distinctive magnetism of NiFe₂O₄@P-g-C₃N₄ aided the collection and recycling of the photocatalyst.

Bimetallic PtAu Alloy Nanoparticles-Integrated g-C3N4 Hybrid as an Efficient Photocatalyst for Water-to-Hydrogen Conversion

Herein, we report the synthesis of metal (Pt and Au) and metal alloy (PtAu) nanoparticles (NPs)-integrated graphitic carbon nitride (g-C₃N₄) hybrids using a facile solvothermal route for water-splitting application. The metal and metal alloy NPs with varying percentages of Pt and Au are found to be in the size range of 3-5 nm and uniformly distributed on the g-C₃N₄ sheets. The metal and metal alloy NPs act as cocatalyst for g-C₃N₄ to enhance the photocatalytic activity for hydrogen (H₂) generation through higher light absorption and efficient charge separation. The alloy composition plays an important role to maximize the photoactivity, with an optimized PtAu/g-C₃N₄ sample delivered 1009 μmol g^-1 h^-1 of H₂. The visible light assisted photocatalytic H₂ evolution is further investigated with the optimized PtAu alloy NPs-integrated g-C₃N₄. This study presents a robust, stable, and easily synthesizable PtAu/g-C₃N₄ hybrid material as a promising photocatalyst for H₂ generation through water splitting.

A novel n-type CdS nanorods/p-type LaFeO3 heterojunction nanocomposite with enhanced visible-light photocatalytic performance

In this work, a novel n-type CdS nanorods/p-type LaFeO₃ (CdS NRs/LFO) nanocomposite was prepared, for the first time, via a facile solvothermal method. The as-prepared n-CdS NRs/p-LFO nanocomposite was characterized by using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy (EDX), UV-visible diffuse reflection spectroscopy (DRS), vibrating sample magnetometry (VSM), photoluminescence (PL) spectroscopy, and Brunauer–Emmett–Teller (BET) surface area analysis. All data revealed the attachment of the LFO nanoparticle on the surface of CdS NRs. This novel nanocomposite was applied as a novel visible light photocatalyst for the degradation of methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) dyes under visible-light irradiation. Under optimized conditions, the degradation efficiency was 97.5% for MB, 80% for RhB and 85% for MO in the presence of H₂O₂ and over CdS NRs/LFO nanocomposite. The photocatalytic activity of CdS NRs/LFO was almost 16 and 8 times as high as those of the pristine CdS NRs and pure LFO, respectively. The photocatalytic activity was enhanced mainly due to the high efficiency in separation of electron–hole pairs induced by the remarkable synergistic effects of CdS and LFO semiconductors. After the photocatalytic reaction, the nanocomposite can be easily separated from the reaction solution and reused several times without loss of its photocatalytic activity. Trapping experiments indicated that ·OH radicals were the main reactive species for dye degradation in the present photocatalytic system. On the basis of the experimental results and estimated energy band positions, the mechanism for the enhanced photocatalytic activity was proposed.

A novel n–p CdS nanorods/LaFeO₃ (CdS NRs/LFO) heterojunction nanocomposite was prepared via a solvothermal route and applied as a visible-light photocatalyst for enhanced degradation of organic dye pollutants.

Construction of a 0D/1D composite based on Au nanoparticles/CuBi2O4 microrods for efficient visible-light-driven photocatalytic activity

Photocatalysis is considered to be a promising technique for the degradation of organic pollutants. Herein, a 0D/1D composite photocatalyst consisting of Au nanoparticles (NPs) and CuBi₂O₄ microrods (Au/CBO) was designed and prepared by a simple thermal reduction-precipitation approach. It shows excellent photocatalytic performance in the degradation of tetracycline (TC). The maximum photocatalytic degradation rate constant for Au/CBO composites with 2.5 wt % Au NPs was 4.76 times as high as that of bare CBO microrods. Additionally, the 0D/1D Au/CBO composite also exhibited ideal stability. The significant improvement of the photocatalytic performance could be attributed to the improved light harvesting and increased specific surface area, enhancing photoresponse and providing more active sites. Our work shows a possible design of efficient photocatalysts for environmental remediation.

Rare earth element, Sm, modified graphite phase carbon nitride heterostructure for photocatalytic hydrogen production

A new type of Sm₂O₃@Ni₇S₆/g-C₃N₄ composite has high photocatalytic activity and stability.

Fabrication and photocatalytic property of magnetic SrTiO3/NiFe2O4 heterojunction nanocomposites

Novel multifunctional SrTiO₃/NiFe₂O₄ nanocomposites were successfully fabricated via a two-step route. The as-prepared samples were characterized by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), field-emission transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy and vibrating sample magnetometry (VSM). The results indicate that the SrTiO₃/NiFe₂O₄ heterostructures are composed of SrTiO₃ spheroidal nanoparticles adhered to NiFe₂O₄ polyhedra. The heterojunction established in the composite material accelerates the process of electron–hole pair separation and boosts the photo-Fenton reaction. Among the samples, 15 wt% SrTiO₃/NiFe₂O₄ nanocomposites exhibit a powerful light response and excellent room temperature ferromagnetism. Subsequently, the photocatalytic degradation of RhB over the as-prepared samples was investigated and optimized, revealing that the 15 wt% SrTiO₃/NiFe₂O₄ nanocomposites exhibit the best photocatalytic activity and stability under simulated solar light irradiation. Furthermore, according to experimental results, the possible mechanism of improved photocatalytic activity was also proposed.

Photocatalytic degradation of RhB for all samples under simulated solar light illumination and absorption spectra of RhB over 15 wt% SrTiO₃/NiFe₂O₄ nanocomposites.

Au nanoparticle-doped Co3O4–CoFe2O4@SiO2 as a catalyst for visible-light-driven water oxidation

Composites of low dielectric constant SiO₂, Au and metal oxide was obtained, it showed higher O₂ evolution performance due to enhancing the electron transfer rate.

Environmentally sustainable biogenic fabrication of AuNP decorated-graphitic g-C3N4 nanostructures towards improved photoelectrochemical performances

Proposed schematic model for the biogenic synthesis of Au-g-C₃N₄ nanostructures using an environment-friendly approach.