Visible‐Light Photocatalytic Activity and Deactivation Mechanism of Ag 3 PO 4 Spherical Particles

Near-Infrared Light-Induced Reversible Deactivation Radical Polymerization: Expanding Frontiers in Photopolymerization

Photoinduced reversible deactivation radical polymerization (photo-RDRP) or photoinduced controlled/living radical polymerization has emerged as a versatile and powerful technique for preparing functional and advanced polymer materials under mild conditions by harnessing light energy. While UV and visible light (λ = 400-700 nm) are extensively employed in photo-RDRP, the utilization of near-infrared (NIR) wavelengths (λ = 700-2500 nm) beyond the visible region remains relatively unexplored. NIR light possesses unique properties, including enhanced light penetration, reduced light scattering, and low biomolecule absorption, thereby providing opportunities for applying photo-RDRP in the fields of manufacturing and medicine. This comprehensive review categorizes all known NIR light-induced RDRP (NIR-RDRP) systems into four mechanism-based types: mediation by upconversion nanoparticles, mediation by photocatalysts, photothermal conversion, and two-photon absorption. The distinct photoinitiation pathways associated with each mechanism are discussed. Furthermore, this review highlights the diverse applications of NIR-RDRP reported to date, including 3D printing, polymer brush fabrication, drug delivery, nanoparticle synthesis, and hydrogel formation. By presenting these applications, the review underscores the exceptional capabilities of NIR-RDRP and offers guidance for developing high-performance and versatile photopolymerization systems. Exploiting the unique properties of NIR light unlocks new opportunities for synthesizing functional and advanced polymer materials.

Novel Ag-bridged dual Z-scheme g-C3N4/BiOI/AgI plasmonic heterojunction: Exceptional photocatalytic activity towards tetracycline and the mechanism insight

Rational design and synthesis of highly efficient and robust photocatalysts with positive exciton splitting and interfacial charge transfer for environmental applications is critical. Herein, aiming at overcoming the common shortcomings of traditional photocatalysts such as weak photoresponsivity, rapid combination of photo-generated carriers and unstable structure, a novel Ag-bridged dual Z-scheme g-C₃N₄/BiOI/AgI plasmonic heterojunction was successfully synthesized using a facile method. Results showed that Ag-AgI nanoparticles and three-dimensional (3D) BiOI microspheres were decorated highly uniformly on the 3D porous g-C₃N₄ nanosheet, resulting in a higher specific surface area and abundant active sites. The optimized 3D porous dual Z-scheme g-C₃N₄/BiOI/Ag-AgI manifested exceptional photocatalytic degradation efficiency of tetracycline (TC) in water with approximately 91.8% degradation efficiency within 165 min, outperforming majority of the reported g-C₃N₄-based photocatalysts. Moreover, g-C₃N₄/BiOI/Ag-AgI exhibited good stability in terms of activity and structure. In-depth radical scavenging and electron paramagnetic resonance (EPR) analyses confirmed the relative contributions of various scavengers. Mechanism analysis indicated that the improved photocatalytic performance and stability were ascribed to the highly ordered 3D porous framework, fast electron transfer of dual Z-scheme heterojunction, desirable photocatalytic performance of BiOI/AgI and synergistic effect of Ag plasmas. Therefore, the 3D porous Z-scheme g-C₃N₄/BiOI/Ag-AgI heterojunction had a good prospect for applications in water remediation. The current work provides new insight and useful guidance for designing novel structural photocatalysts for environment-related applications.

Recyclable Carbon Cloth-Supported ZnO@Ag3PO4 Core-Shell Structure for Photocatalytic Degradation of Organic Dye

The extensive use of organic dyes in industry has caused serious environmental problems, and photocatalysis is a potential solution to water pollution by organic dyes. The practical application of powdery photocatalysts is usually limited by the rapid recombination of charge carriers and difficulty in recycling. In this study, recyclable carbon cloth-supported ZnO@Ag₃PO₄ composite with a core-shell structure was successfully prepared by solvothermal treatment and subsequent impregnation-deposition. The as-prepared carbon cloth-supported ZnO@Ag₃PO₄ composite showed an improved photocatalytic activity and stability for the degradation of rhodamine B (RhB), a model organic dye, under visible light irradiation. The decomposition ratio of RhB reached 87.1% after exposure to visible light for 100 min, corresponding to a reaction rate constant that was 4.8 and 15.9 times that of carbon cloth-supported Ag₃PO₄ or ZnO alone. The enhanced performance of the composite can be attributed to the effectively inhibited recombination of photoinduced electron-hole pairs by the S-scheme heterojunction. The carbon fibers further promoted the transfer of charges. Moreover, the carbon cloth-supported ZnO@Ag₃PO₄ can be easily separated from the solution and repeatedly used, demonstrating a fair recyclability and potential in practical applications.

A Targeted Review of Current Progress, Challenges and Future Perspective of g-C3 N4 based Hybrid Photocatalyst Toward Multidimensional Applications

The increasing demand for searching highly efficient and robust technologies in the context of sustainable energy production totally rely onto the cost-effective energy efficient production technologies. Solar power technology in this regard will perceived to be extensively employed in a variety of ways in the future ahead, in terms of the combustion of petroleum-based pollutants, CO₂ reduction, heterogeneous photocatalysis, as well as the formation of unlimited and sustainable hydrogen gas production. Semiconductor-based photocatalysis is regarded as potentially sustainable solution in this context. g-C₃ N₄ is classified as non-metallic semiconductor to overcome this energy demand and enviromental challenges, because of its superior electronic configuration, which has a median band energy of around 2.7 eV, strong photocatalytic stability, and higher light performance. The photocatalytic performance of g-C₃ N₄ is perceived to be inadequate, owing to its small surface area along with high rate of charge recombination. However, various synthetic strategies were applied in order to incorporate g-C₃ N₄ with different guest materials to increase photocatalytic performance. After these fabrication approaches, the photocatalytic activity was enhanced owing to generation of photoinduced electrons and holes, by improving light absorption ability, and boosting surface area, which provides more space for photocatalytic reaction. In this review, various metals, non-metals, metals oxide, sulfides, and ferrites have been integrated with g-C₃ N₄ to form mono, bimetallic, heterojunction, Z-scheme, and S-scheme-based materials for boosting performance. Also, different varieties of g-C₃ N₄ were utilized for different aspects of photocatalytic application i. e., water reduction, water oxidation, CO₂ reduction, and photodegradation of dye pollutants, etc. As a consequence, we have assembled a summary of the latest g-C₃ N₄ based materials, their uses in solar energy adaption, and proper management of the environment. This research will further well explain the detail of the mechanism of all these photocatalytic processes for the next steps, as well as the age number of new insights in order to overcome the current challenges.

Room-temperature synthesis of Ag3PO4 nanoparticles with the assistance of trisodium citrate for photocatalytic dye degradation

The Ag3PO4 NPs had a high photocatalytic activity in MB degradation under visible-light illumination. The photocatalytic activity reduced by 4.4% after 5 cycles.

Hydrogen production via water splitting over graphitic carbon nitride (g-C3N4 )-based photocatalysis

Photocatalytic splitting of water into hydrogen and oxygen using semiconductor photocatalysts and light irradiation has been attracted much attention and considered to be an alternative for nonrenewable fossil fuel to solve environmental problems and energy crisis and also an as promising approach to produce clean, renewable hydrogen fuel. Owing to their various advantages such as low cost and environmental friendly, chemical, and thermal stability, appropriate band structure, graphitic carbon nitride (g-C3N4 ) photocatalysts have gained multitudinous attention because of their great potential in solar fuels production and environmental remediation. However, due to its fast charge carrier’s recombination, low surface, and limited absorption of the visible light restrict their activity toward hydrogen evolution and numerous modification techniques were applied to solve these problems such as structural modification, metal/nonmetal doping, and noble metal loading, and coupling semiconductors. In this chapter, we summarize recent progress in the synthesis and characterization of the g-C3N4-based photocatalyst. Several modification methods used to enhance the photocatalytic hydrogen production of g-C3N4-based photocatalyst were also highlighted. This chapter ends with the future research and challenges of hydrogen production over g-C3N4-based photocatalyst.

Porous hollow Ag/Ag2S/Ag3PO4 nanocomposites as highly efficient heterojunction photocatalysts for the removal of antibiotics under simulated sunlight irradiation

Antibiotic pollutants are a serious and growing threat to human health and the environment that efficient measures must be taken to eliminate them. Here, we report the facile fabrication of porous hollow Ag/Ag₂S/Ag₃PO₄ heterostrucutres for efficient photocatalytic degradation of tetracycline under simulated sunlight irradiation. The morphology manipulation and hetero-nanocomposites construction through a coprecipitation-refluxing approach were applied to enhance the photocatalytic performance of the Ag/Ag₂S/Ag₃PO₄ products. The photodegradation outcomes indicated that the heterojunction Ag/Ag₂S/Ag₃PO₄ photocatalyst with a suitable band gap energy of 2.17 eV, has better degradation performance (∼95%) than individual Ag₂S and Ag₃PO₄ structures after 120 min of simulated sunlight irradiation, even after five recycles. The good photocatalytic activity of Ag/Ag₂S/Ag₃PO₄ nanocomposites could be mainly attributed to the unique hierarchical architectures, promoted visible-light harvesting, reduced a recombination and boosted separation of electron-hole pairs originated from the as-formed heterojunctions. Moreover, we proposed a photocatalytic degradation mechanism based on the radical scavenging results, which disclosed that the ^•O₂^- and ^•OH species perform essential tasks for the photodegradation of antibiotics by Ag/Ag₂S/Ag₃PO₄ nanocomposites.

A novel approach for the synthesis of nanostructured Ag3PO4 from phosphate rock: high catalytic and antibacterial activities

BACKGROUND

Silver orthophosphate (Ag3PO4) has received enormous attention over the past few years for its higher visible light photocatalytic performance as well as for various organic pollutants degradation in aqueous media. Therefore, considerable efforts have been made to the synthesis of Ag3PO4 with high catalytic efficiency, long lifetime, and using low-cost inorganic precursors.

RESULTS

This article describes our efforts to develop a novel approach to synthesize of nanostructured silver phosphate (Ag3PO4) using phosphate rock as alternative and natural source of PO43- precursor ions. The catalytic experimental studies showed that the nanostructured Ag3PO4 exhibited excellent catalytic activity for reduction of p-nitrophenol in the presence of NaBH4 at room temperature. Furthermore, the antibacterial studies revealed that the obtained Ag3PO4 possess significant effect against E. Coli and S. Aureus bacteria.

CONCLUSION

The obtained results make the nanostructured Ag3PO4 prepared from natural phosphate as a highly promising candidate to be used as efficient catalyst and antibacterial agent.

Structure, Photoluminescence Emissions, and Photocatalytic Activity of Ag2SeO3: A Joint Experimental and Theoretical Investigation

In this paper, we report the synthesis of silver selenite (Ag₂SeO₃) by different methods [sonochemistry, ultrasonic probe, coprecipitation, and microwave-assisted hydrothermal methods]. These microcrystals presented a structural long-range order as confirmed by X-ray diffraction (XRD) and Rietveld refinements and a structural short-range order as confirmed by Fourier transform infrared (FTIR) and Raman spectroscopies. X-ray photoelectron spectroscopy (XPS) provided information about the surface of the samples indicating that they were pure. The microcrystals presented different morphologies and sizes due to the synthesis method as observed by field emission scanning electron microscopy (FE-SEM). The optical properties of these microcrystals were evaluated by ultraviolet-visible (UV-vis) spectroscopy and photoluminescence (PL) measurements. Thermal analysis confirmed the temperature stability of the as-synthetized samples. Further trapping experiments prove that the holes and hydroxyl radicals, to a minor extent, are responsible for the photocatalytic reactions. The experimental results are sustained by first-principles calculations, at the density functional theory (DFT) level, to decipher the structural parameters, electronic properties of the bulk, and surfaces of Ag₂SeO₃. By matching the experimental FE-SEM images and theoretical morphologies, we are capable of finding a correlation between the morphology and photocatalytic activity, along with photodegradation of the Rhodamine B dye under UV light, based on the different numbers of unsaturated superficial Ag and Se cations (local coordination, i.e., clusters) of each surface.

In-situ growth of high-density ultrafine Ag3PO4 nanoparticles on 3D TiO2 hierarchical spheres for enhanced photocatalytic degradation of organic pollutants

Silver phosphate (Ag₃PO₄, APO) has attracted intense attention as a visible-light-driven photocatalyst, but its large-scale application is limited by severe charge recombination and inevitable photo-corrosion. Various rational APO-based heterostructures composed of APO nanoparticles (NPs) and band-matched semiconductor support are designed to address the above issues. Nevertheless, the size, density, stability, and dispersion of APO NPs are critical challenges for the photocatalytic performance of APO-based photocatalysts. Here, three-dimensional (3D) self-assembled TiO₂ hierarchical spheres (THS) prepared by a simple one-step hydrothermal method are employed as innovative support, and ultrafine high-density APO NPs with an average size of about 3 nm are successfully deposited and uniformly dispersed throughout THS to form hierarchical THS/APO composites. The novel THS/APO microstructure provides abundant reactive sites for photocatalytic reactions and promotes the photogenerated charge separation and transfer due to the ultrafine size of APO NPs and the TiO₂/APO Type-II heterojunction. As a result, the THS/APO composites show significant improvement in photocatalytic activity and stability in methylene blue (MB) degradation. The reaction constant of THS/APO composites far exceeds that of either THS or APO, roughly 16 and 7 times higher than that of THS and APO under full-spectrum light, and 41 and 4 times higher under visible light. Our results strongly suggest new insights into the low-cost, large-scale application of high-efficiency APO-based photocatalyst.

Novel Pt-Ag3PO4/CdS/Chitosan Nanocomposite with Enhanced Photocatalytic and Biological Activities

Decorating photocatalysts with noble metal nanoparticles (e.g., Pt) often increases the catalysts' photocatalytic activity and biomedical properties. Here, a simple and inexpensive method has been developed to prepare a Pt-Ag3PO4/CdS/chitosan composite, which was characterized and used for the visible light-induced photocatalytic and antibacterial studies. This synthesized composite showed superior photocatalytic activity for methylene blue degradation as a hazardous pollutant (the maximum dye degradation was observed in 90 min of treatment) and killing of Gram positive bacterial (Staphylococcus aureus and Bacillus cereus) as well as Gram negative bacteria (Klebsiella pneumoniae, Salmonella typhimurium, Escherichia coli, and Pseudomonas aeruginosa) under visible light irradiation. The antibacterial activity of CdS, CdS/Ag3PO4, and Pt-Ag3PO4/CdS/chitosan against E. coli, Pseudomonas aeruginosa, Salmonella typhimurium, Klebsiella pneumoniae, Staphylococcus aureus, and Bacillus cereus showed the zone of inhibition (mm) under visible light and under dark conditions at a concentration of 20 µg mL-1. Furthermore, the cell viability of the CdS/chitosan, Ag3PO4, Ag3PO4/CdS/chitosan, and Pt-Ag3PO4/CdS/chitosan were investigated on the human embryonic kidney 293 cells (HEK-293), Henrietta Lacks (HeLa), human liver cancer cell line (HepG2), and pheochromocytoma (PC12) cell lines. In addition, the results indicated that the photodegradation rate for Pt-Ag3PO4/CdS/chitosan is 3.53 times higher than that of CdS and 1.73 times higher than that of the CdS/Ag3PO4 composite. Moreover, Pt-Ag3PO4/CdS/chitosan with an optimal amount of CdS killed large areas of different bacteria and different cells separately in a shorter time period under visible-light irradiation, which shows significantly higher efficiency than pure CdS and other CdS/Ag3PO4 composites. The superb performances of this composite are attributed to its privileged properties, such as retarded recombination of photoinduced electron/hole pairs and a large specific surface area, making Pt-Ag3PO4/CdS/chitosan a valuable composite that can be deployed for a range of important applications, such as visible light-induced photocatalysis and antibacterial activity.

Eco-friendly synthesis of self-regenerative low-cost biosorbent by the incorporation of CuO: a photocatalyst sensitive to visible light irradiation for azo dye removal

Acid pretreated biomass Lemna minor (BM-H3PO4) was used as support for CuO nanoparticles loading, to investigate the dye biosorption capacity and the photocatalytic performance under artificial visible light. The surface morphology, crystal structure, elemental composition, and the bandgap of modified biomass have been determined using FE-SEM, XRD, EDX, XPS, FTIR, and UV-DR analysis. The results showed that NH2 and P-O functional groups of (BM-H3PO4) can attract the copper ions (Cu2+), which can facilitate the loading of CuO nanoparticles hence, smaller nanoparticles with an average diameter of 21 nm was obtained. It was also found that when the CuO was incorporated in BM-H3PO4 in a proper mass ratio of 0.4, the biosorption efficiency was enhanced to 3 times compared with BM-H3PO4 and reached a maximum of 91%, at a dye concentration of 20 mg/L, solution pH equal to 5, and an ambient temperature of 25 °C. Furthermore, CuO-modified BM-H3PO4 exhibits a better photocatalytic activity than pure CuO in the presence of H2O2 and visible light irradiation, where the dye was completely removed and mineralized after 240 min, evidenced by COD measurement. The photocatalytic regeneration also shows that the biosorption efficiency was maintained at 91% over 3 cycles, indicating the significant self-regenerative capacity of the biosorbent.

Unraveling the relationship between exposed surfaces and the photocatalytic activity of Ag3PO4: an in-depth theoretical investigation

Over the years, the possibility of using solar radiation in photocatalysis or photodegradation processes has attracted remarkable interest from scientists around the world. In such processes, due to its electronic properties, Ag₃PO₄ is one of the most important semiconductors. This work delves into the photocatalytic activity, stability, and reactivity of Ag₃PO₄ surfaces by comparing plane waves with projector augmented wave and localized Gaussian basis set simulations, at the atomic level. The results indicate that the (110) surface, in agreement with previous experimental reports, displays the most suitable characteristics for photocatalytic activity due to its high reactivity, i.e. the presence of a large amount of undercoordinated Ag cations and a high value work function. Beyond the innovative results, this work shows a good synergy between both kinds of DFT approaches.

Electrochemically Driven Formation of Sponge-Like Porous Silver Nanocubes Toward Efficient CO2 Electroreduction to CO

Electrochemical conversion of CO₂ into valuable products by utilizing renewable electricity is a thriving research field. For electrochemical reduction of CO₂ to CO, uniform sponge-like porous Ag nanocubes (SPC-Ag) integrated on carbon paper are prepared by using an electrochemically driven method. The SPC-Ag has a 3 D porous structure and a large specific surface area, which affords abundant active sites for the CO₂ reduction reaction (CO₂ RR), as well as reducing impedance to accelerate the CO₂ RR kinetics. This distinctive organization affords SPC-Ag with outstanding electrocatalytic performance for CO₂ reduction to CO. High faradaic efficiency (>90 %) and large partial current density for CO with excellent durability are observed in a wide potential window, with a maximum value of 93 % at -0.9 V versus reversible hydrogen electrode.

Photoenergy Conversion Behaviors of Photoluminescence and Photocatalysis in Silver-Coated LiBaPO4:Eu2

LiBaPO₄:Eu²⁺ phosphor and Ag-coated LiBaPO₄:Eu²⁺ composites (Ag/LiBaPO₄:Eu²⁺) were prepared via solid-state reaction and traditional photoreduction methods, respectively. The samples were characterized via XRD, SEM, and UV-vis optical absorption spectroscopy. Two photoenergy conversion processes, namely, photocatalysis and photoluminescence, were investigated in detail. In comparison with as-prepared LiBaPO₄:Eu²⁺ phosphor, Ag-modified composites exhibited the enhanced photocatalytic effects together with the quenched Eu²⁺ luminescence. A Schottky barrier was created on the interface between Ag nanoparticles and LiBaPO₄ host, thereby greatly delaying the recombination between the light-induced holes and electrons. A photoenergy conversion mechanism was suggested and discussed on the basis of the experiments. The Eu²⁺ ion luminescence centers directly participated in the photodegradation with the meditation of Ag nanoparticles on the surface. With the increase of the Ag coating level on the surfaces, some emission peaks corresponding to ⁵D₀ → ⁷F_0,1,2,3,4 transitions of Eu³⁺ ions were detected. Eu²⁺/Eu³⁺ couples also play an important role in improving photocatalysis. LiBaPO₄:Eu²⁺ phosphor is a good candidate for the investigation of multimodal photoenergies of photoluminescence and photocatalysis.

Localized Surface Plasmon Resonance Meets Controlled/Living Radical Polymerization: An Adaptable Strategy for Broadband Light-Regulated Macromolecular Synthesis

The photophysical process of localized surface plasmon resonance (LSPR) is, for the first time, exploited for broadband photon harvesting in photo-regulated controlled/living radical polymerization. Efficient macromolecular synthesis was achieved under illumination with light wavelengths extending from the visible to the near-infrared regions. Plasmonic Ag nanostructures were in situ generated on Ag₃ PO₄ photocatalysts in a reversible addition-fragmentation chain transfer (RAFT) system, thereby promoting polymerization of various monomers following a LSPR-mediated electron transfer mechanism. Owing to the LSPR-enhanced broadband photon harvesting, high monomer conversion (>99 %) was achieved under natural sunlight within 0.8 h. The deep penetration of NIR light enabled successful polymerization with reaction vessels screened by opaque barriers. Moreover, by trapping active oxygen species generated in the photocatalytic process, polymerization could be implemented without pre-deoxygenation.

A Ternary Magnetic Recyclable ZnO/Fe3O4/g-C3N4 Composite Photocatalyst for Efficient Photodegradation of Monoazo Dye

To develop a highly efficient visible light-induced and conveniently recyclable photocatalyst, in this study, a ternary magnetic ZnO/Fe₃O₄/g-C₃N₄ composite photocatalyst was synthesized for the photodegradation of Monas dye. The structure and optical performance of the composite photocatalyst were characterized using X-ray diffraction (XRD), transmission electron microscopye (TEM), energy dispersive spectroscopy (EDS), photoluminescence (PL) spectra, ultraviolet-visible diffuse reflection, and photo-electrochemistry. The photocatalytic activities of the prepared ZnO/Fe₃O₄/g-C₃N₄ nanocomposites were notably improved, and they were significantly higher than those of pure g-C₃N₄ and ZnO. Given the presence of the heterojunction between the interfaces of g-C₃N₄ and ZnO, the higher response to visible light and separation efficiency of the photo-induced electrons and holes enhanced the photocatalytic activities of the ZnO/Fe₃O₄/g-C₃N₄ nanocomposites. The stability experiment revealed that ZnO/Fe₃O₄/g-C₃N₄-50% demonstrates a relatively higher photocatalytic activity after 5 recycles. The degradation efficiency of MO, AYR, and OG over ZnO/Fe₃O₄/g-C₃N₄-50% were 97.87%, 98.05%, and 83.35%, respectively, which was due to the number of dye molecules adsorbed on the photocatalyst and the structure of the azo dye molecule. Azo dyes could be effectively and rapidly photodegraded by the obtained photocatalyst. Therefore, the environment-friendly photocatalyst could be widely applied to the treatment of dye contaminated wastewater.

Controllable fabrication of α-Ag2WO4 nanorod-clusters with superior simulated sunlight photocatalytic performance

This work presents the greatly boosted photoactivity of α-Ag₂WO₄ nanorod-clusters fabricated by adjusting the molar ratio of raw materials.

Deep Oxidation of NO by a Hybrid System of Plasma-N-Type Semiconductors: High-Energy Electron-Activated "Pseudo Photocatalysis" Behavior

A "pseudo photocatalysis" process, being initiated between plasma and N-type semiconductors in the absence of light, was investigated for NO removal for the first time via dynamic probing of reaction processes by FT-IR spectra. It was demonstrated that N-type semiconductor catalysts could be activated to produce electron-hole (e^--h⁺) pairs by the collision of high-energy electrons (e*) from plasma. Due to the synergy of plasma and N-type semiconductors, major changes were noted in the conversion pathways and products. NO can be directly converted to NO₂^- and NO₃^- instead of toxic NO₂, owing to the formation of O₂^- and ·OH present in catalysts. New species like O₃ or ·O may be generated from the interaction between catalyst-induced species and radicals in plasma at a higher SIE, leading to deep oxidation of existing NO₂ to N₂O₅. Experiments with added trapping agents confirmed the contribution of e^- and h⁺ from catalysts. A series of possible reactions were proposed to describe reaction pathways and the mechanism of this synergistic effect. We established a novel system and realized an e*-activated "pseudo photocatalysis" behavior, facilitating the deep degradation of NO. We expect that this new strategy would provide a new idea for in-depth analysis of plasma-activated catalysis phenomenon.

Insights Into Highly Improved Solar-Driven Photocatalytic Oxygen Evolution Over Integrated Ag3PO4/MoS2 Heterostructures

Oxygen evolution has been considered as the rate-determining step in photocatalytic water splitting due to its sluggish four-electron half-reaction rate, the development of oxygen-evolving photocatalysts with well-defined morphologies and superior interfacial contact is highly important for achieving high-performance solar water splitting. Herein, we report the fabrication of Ag₃PO₄/MoS₂ nanocomposites and, for the first time, their use in photocatalytic water splitting into oxygen under LED light illumination. Ag₃PO₄ nanoparticles were found to be anchored evenly on the surface of MoS₂ nanosheets, confirming an efficient hybridization of two semiconductor materials. A maximum oxygen-generating rate of 201.6 μmol · L⁻¹ · g⁻¹ · h⁻¹ was determined when 200 mg MoS₂ nanosheets were incorporated into Ag₃PO₄ nanoparticles, which is around 5 times higher than that of bulk Ag₃PO₄. Obvious enhancements in light-harvesting property, as well as electron-hole separation and charge transportation are revealed by the combination of different characterizations. ESR analysis verified that more active oxygen-containing radicals generate over illuminated Ag₃PO₄/MoS₂ composite photocatalysts rather than irradiated Ag₃PO₄. The improvement in oxygen evolution performance of Ag₃PO₄/MoS₂ composite photocatalysts is ascribed to wide spectra response in the visible-light region, more efficient charge separation, and enhanced oxidation capacity in the valence band (VB). This study provides new insights into the design and development of novel composite photocatalytic materials for solar-to-fuel conversion.

Oxygen vacancies of the TiO2nano-based composite photocatalysts in visible light responsive photocatalysis

The TiO₂nano-based composite photocatalyst is best known for application in solving the recent issues related to energy and environmental purification.

A novel Bi4Ti3O12/Ag3PO4 heterojunction photocatalyst with enhanced photocatalytic performance

In this work, we integrated Ag₃PO₄ with Bi₄Ti₃O₁₂ to form Bi₄Ti₃O₁₂/Ag₃PO₄ heterojunction nanocomposites by an ion-exchange method. The as-prepared Bi₄Ti₃O₁₂/Ag₃PO₄ composites were systematically characterized by means of XRD, SEM, TEM, BET, XPS, UV-vis DRS, EIS, PL spectroscopy, and photocurrent response. SEM, TEM, and XPS results demonstrate the creation of Bi₄Ti₃O₁₂/Ag₃PO₄ heterojunction with obvious interfacial interaction between Bi₄Ti₃O₁₂ and Ag₃PO₄. PL spectra, EIS spectra, and photocurrent responses reveal that the composites display an enhanced separation efficiency of photogenerated electron-hole pairs, which is due to the charge transfer between Bi₄Ti₃O₁₂ and Ag₃PO₄. Rhodamine B (RhB) was chosen as the target organic pollutant to evaluate its degradation behavior over Bi₄Ti₃O₁₂/Ag₃PO₄ composites under simulated sunlight irradiation. Compared to bare Bi₄Ti₃O₁₂ and Ag₃PO₄ nanoparticles, the composites exhibit a significantly enhanced photocatalytic activity. The highest photocatalytic activity is observed for the 10% Bi₄Ti₃O₁₂/Ag₃PO₄ composite with 10% Bi₄Ti₃O₁₂ content, which is about 2.6 times higher than that of bare Ag₃PO₄. The photocatalytic mechanism involved was investigated and discussed in detail.

Two-dimensional bismuth oxybromide coupled with molybdenum disulphide for enhanced dye degradation using low power energy-saving light bulb

In the present work, two-dimensional bismuth oxybromide (BiOBr) was synthesized and coupled with co-catalyst molybdenum disulphide (MoS₂) via a simple hydrothermal process. The photoactivity of the resulting hybrid photocatalyst (MoS₂/BiOBr) was evaluated under the irradiation of 15 W energy-saving light bulb at ambient condition using Reactive Black 5 (RB5) as model dye solution. The photo-degradation of RB5 by BiOBr loaded with 0.2 wt% MoS₂ (MoBi-2) exhibited more than 1.4 and 5.0 folds of enhancement over pristine BiOBr and titanium dioxide (Degussa, P25), respectively. The increased photocatalytic performance was a result of an efficient migration of excited electrons from BiOBr to MoS₂, prolonging the electron-hole pairs recombination rate. A possible charge transfer diagram of this hybrid composite photocatalyst, and the reaction mechanism for the photodegradation of RB5 were proposed.

Rational Design of Wide Spectral-Responsive Heterostructures of Au Nanorod Coupled Ag3PO4 with Enhanced Photocatalytic Performance

Noble metallic nanomaterials with surface plasmon resonance (SPR) effects and hot electron cell effects open new opportunities for designing efficient visible-light-driven hybrid photocatalysts. In this work, we reported a broadband visible-light responsive photocatalyst by incorporating Au nanorods (AuNRs) into Ag₃PO₄ nanostructures. The longitudinal plasma of AuNRs enabled AuNRs/Ag₃PO₄ heterostructures to harvest light energy up to 800 nm. The obtained AuNRs/Ag₃PO₄ hybrid exhibited enhanced photocatalytic efficiency toward the degradation of rhodamine B (RhB) under solar irradiation. Ag₃PO₄, RhB, and AuNRs played different roles according to the distinct optical properties of each individual component. The dominant photocatalytic process in the different light regions were divided as follows: direct excitation of Ag₃PO₄ for λ ≥ 420 nm, RhB sensitization for λ ≥ 550 nm, and SPR effect for λ ≥ 600 nm. The relationship between the pathway of charge transfer and the photocatalytic activity of the AuNRs/Ag₃PO₄ heterostructures was investigated systematically, revealing the specific role of AuNRs in regulating the photocatalytic activity. This work presents an innovative strategy for determining the comprehensive function of the SPR effect in relevant semiconductor-based photocatalysis and functional nanodevices with a broadband light responses.

Molten Ag2 SO4 -based Ion-Exchange Preparation of Ag0.5 La0.5 TiO3 for Photocatalytic O2 Evolution

Ag_0.5 La_0.5 TiO₃ with an ABO₃ perovskite structure was synthesized by a newly developed ion-exchange method. Molten Ag₂ SO₄ instead of traditional molten AgNO₃ was used as Ag⁺ source in view of its high decomposition temperature (1052 °C), thereby guaranteeing the complete substitution of Ag⁺ for Na⁺ in Na_0.5 La_0.5 TiO₃ with a stable ABO₃ perovskite structure at a high ion-exchange temperature (700 °C). Under full-arc irradiation, the O₂ -evolution activity of Ag_0.5 La_0.5 TiO₃ was about 1.6 times that of Na_0.5 La_0.5 TiO₃ due to the optimized electronic band structures and local lattice structures. On the one hand, the substitution of Ag⁺ for Na⁺ elevated the VBM and thus narrowed the band gap from 3.19 to 2.83 eV, thereby extending the light-response range and, accordingly, enhancing the photoexcitation to generate more charge carriers. On the other hand, the substitution of Ag⁺ for Na⁺ induced a lattice distortion of the ABO₃ perovskite structure, thereby promoting the separation and migration of charge carriers. Moreover, under visible-light irradiation, Ag_0.5 La_0.5 TiO₃ displayed notable O₂ evolution whereas Na_0.5 La_0.5 TiO₃ showed little O₂ evolution, thus demonstrating that the substitution of Ag⁺ for Na⁺ enabled the use of visible light to evolve O₂ photocatalytically. This work presents an effective route to explore novel Ag-based photocatalysts.

Light-Steered Isotropic Semiconductor Micromotors

Intelligent photoresponsive isotropic semiconductor micromotors are developed by taking advantage of the limited penetration depth of light to induce asymmetrical surface chemical reactions. Independent of the Brownian motion of themselves, the as-proposed isotropic micromotors are able to continuously move with both motion direction and speed just controlled by light, as well as precisely manipulate particles for nanoengineering.

Hybrid TiO2/graphene derivatives nanocomposites: is functionalized graphene better than pristine graphene for enhanced photocatalytic activity?

Graphene (GR) and its derivatives are generally assumed to be electron shuttles in order to explain the improved photocatalytic activity of their nanocomposites (such as TiO₂/GR).