3D Aerogel of Graphitic Carbon Nitride Modified with Perylene Imide and Graphene Oxide for Highly Efficient Nitric Oxide Removal under Visible Light

Micro-Spherical BiOI Photocatalysts for Efficient Degradation of Residual Xanthate and Gaseous Nitric Oxide

BiOI microspheres were synthesized using the solvothermal method for the degradation of residual xanthate and gaseous nitric oxide (NO) under visible light irradiation. The as-prepared BiOI nanomaterials were then characterized using various technologies, including XRD, FE-SEM, TEM, UV-Vis DRS, and XPS. The photodegradation results show that the removal efficiency of isobutyl sodium xanthate can reach 98.08% at an initial xanthate concentration of 120 mg/L; that of NO is as high as 96.36% at an inlet NO concentration of 11 ppm. Moreover, the effects of operational parameters such as catalyst dosage, initial xanthate concentration, and pH value of wastewater on the removal of xanthate were investigated. The results of scavenging tests and full-spectrum scanning indicate that ·O2- radicals are the main active species in xanthate degradation, and peroxide xanthate is an intermediate. The reusability of BiOI was explored through cyclic experiments. Furthermore, the reaction path and the mechanism of NO removal using BiOI were analyzed, and the main active species was also ·O2-. It is concluded that BiOI photocatalysts have high potential for wastewater treatment and waste gas clean-up in the mineral industry.

"Floating Catalytic Foam" with prominent heat-induced convection for the effective photocatalytic removal of antibiotics

Immobilized photocatalysts represent a promising candidate for the wastewater treatments due to their good reusability, high stability and low eco-risk. Mass transfer within the immobilized catalytic bed is a crucial process that determines the contacting, adsorption, and degradation kinetics in the photodegradation. In this study, a floating catalytic foam (FCF) with a prominent pumping effect was designed to promote mass transfer. The polyurethane foam immobilized with rGO/TiO2/ultrathin-g-C3N4 photocatalyst (PRTCN) was prepared by a simple dip-coating and Uv-light aging process. It was found that the hydrophilic-hydrophobic interfaces could not only contribute to the floating of the catalyst but also establish a temperature gradient across the floating immobilized catalyst. In addition, the temperature gradient induced convection could serve as a built-in pump to effectively promote the diffusion and adsorption of target antibiotic molecules during the photocatalytic process. Therefore, the PRTCN demonstrated a high photodegradation and mineralization efficiency with excellent reusability and anti-interference capability. Moreover, the photodegradation mechanism and the intermediates' toxicity of norfloxacin were detailly investigated by ultra-high resolution electrospray time-of-flight mass spectrometry, density functional theory simulation and ECOSAR estimation. This work proposed a facile and sustainable strategy to enhance the mass transfer problem on immobilized photocatalysts, which could promote the application of the immobilized photocatalysts in the real water-treatment scenarios.

Microwave-Assisted Rapid Substitution of Ti for Zr to Produce Bimetallic (Zr/Ti)UiO-66-NH2 with Congenetic "Shell-Core" Structure for Enhancing Photocatalytic Removal of Nitric Oxide

Efficient nitric oxide (NO) removal without nitrogen dioxide (NO₂ ) emission is desired for the control of air pollution. Herein, a series of (Zr/Ti)UiO-66-NH₂ with congenetic shell-core structure, denoted as Ti-UION, are rapidly synthesized by microwave-assisted post-synthetic modification for NO removal. The optimal Ti-UION (i.e., 2.5Ti-UION) exhibits the highest activity of 80.74% without NO₂ emission with moisture, which is 21.65% greater than that of the UiO-66-NH₂ . The NO removal efficiency of 2.5Ti-UION further increases to 95.92% without photocatalyst deactivation under an anhydrous condition. This is because selectively produced NO₂ in photocatalysis is completely adsorbed into micropores, refreshing active sites for subsequent reaction. In addition, the enhanced photocatalytic activity after Ti substitution is due to the presence of Ti electron acceptor, the potential difference between the shell and core of Ti-UION crystal, and the high conductivity of TiO units. Additionally, the improved adsorption of gas molecules not only favors NO oxidation, but also avoids the emission of NO₂ . This work provides a feasible strategy for rapid metal substitution in metal-organic frameworks and insights into enhanced NO photodegradation.

Reduced graphene oxide/carbon nitride composite sponge for interfacial solar water evaporation and wastewater treatment

Interfacial solar-driven steam generation has been proposed as a cost-effective green sustainable technology to alleviate the freshwater crisis. However, the desire to produce clean water from water sources containing organic contaminants is still remains a challenge due to the limitations of the traditional wastewater treatment methods. Here, we constructed a g-C3N4-based composite sponge solar steam generator (rGCPP) by a simple hydrothermal reaction. Benefiting from its low cost and easy preparation, this evaporator can be expected to be a promising candidate for the alleviation of water shortages and water pollution in practical applications. By combination of the solar steam generation and the photocatalysis into the rGCPP-based interfacial solar-driven steam generation system, the resulted rGCPP-based solar steam generator performs outstanding solar absorption of 90.8%, which achieves high evaporation rate of 1.875 kg m-2 h-1 and solar-to-vapor efficiency of 81.07% under 1 sun irradiation. Meanwhile, organic pollutants in the water source can be completely removed by photocatalytic degradation and the degradation rates were measured to be 99.20% for methylene blue and 91.07% for rhodamine B, respectively. Consequently, the as-prepared composite sponge has promising applications in generating clean water and alleviating water pollution.

Three-Dimensional Hierarchical Seaweed-Derived Carbonaceous Network with Designed g-C3N4 Nanosheets: Preparation and Mechanism Insight for 4-Nitrophenol Photoreduction

The development of g-C₃N₄-based photocatalysts with abundant active sites is of great significance for photocatalytic reactions. Herein, a smart and robust strategy was presented to fabricate three-dimensional (3D) g-C₃N₄ nanosheet-coated alginate-based hierarchical porous carbon (g-C₃N₄@HPC), including coating melamine on calcium alginate (CA) hydrogel beads, freeze-drying hydrogel beads as well as pyrolysis at high temperatures. The resulting photocatalyst possessed a significantly high surface area and a large amount of interconnected macropores compared with porous carbon without the melamine coating. The unique structural features could effectively inhibit the curling and agglomeration of g-C₃N₄ nanosheets, provide abundant photocatalytic active sites, and promote mass diffusion. Therefore, the g-C₃N₄@HPC composite exhibited remarkable photocatalytic activity and outstanding stability toward the photoreduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH₄ under natural sunlight and simulated visible-light irradiation (λ > 420 nm) using a 300 W xenon lamp. Moreover, the mechanism toward the photocatalytic reaction was extensively studied by quenching experiments and electron spin resonance (ESR) experiments. The results showed that active hydrogen species were able to be achieved by following a dual-channel pathway in the NaBH₄ system, which included photocatalytic reduction of H⁺ ions and photocatalytic oxidation of BH₄^- ions. This work not only opens up a new way to design efficient photocatalysts for various reactions but also provides a reference for an in-depth study of the photoreduction mechanism.

Construction and Activity of an All-Organic Heterojunction Photocatalyst Based on Melem and Pyromellitic Dianhydride

The separation efficiency of photogenerated carriers in the g-C₃ N₄ system could be improved by the construction of all-organic heterojunctions. However, g-C₃ N₄ has a large π-π conjugated plane that induces a low number of amino groups (-NH₂ ), which are the sites of the heterojunction reaction with organic molecules. In this case, few heterojunction knots can be constructed, and the enhancement effect of the heterojunction cannot be fully displayed. In this study, an all-organic heterojunction with PMDA is constructed with melem instead of g-C₃ N₄ . Although the photocatalytic activity of melem is far below that of g-C₃ N₄ , the photocatalytic activity of PI (the all-organic heterojunction constructed with melem) is considerably higher than that of CP (the all-organic heterojunction constructed with g-C₃ N₄ ). This result is attributed to melem that has more -NH₂ groups to form more heterojunction knots, which can enable the effective transfer and separation of electron-hole pairs. These new findings may shed light on the design of all-organic heterojunction photocatalysts.

Singlet Oxygen and Mobile Hydroxyl Radicals Co-operating on Gas-Solid Catalytic Reaction Interfaces for Deeply Oxidizing NOx

Learning from the important role of porphyrin-based chromophores in natural photosynthesis, a bionic photocatalytic system based on tetrakis (4-carboxyphenyl) porphyrin-coupled TiO₂ was designed for photo-induced treating low-concentration NO_x indoor gas (550 parts per billion), achieving a high NO removal rate of 91% and a long stability under visible-light (λ ≥ 420 nm) irradiation. Besides the great contribution of the conventional ^•O₂^- reactive species, a synergic effect between a singlet oxygen (¹O₂) and mobile hydroxyl radicals (^•OH_f) was first illustrated for removing NO_x indoor gas (¹O₂ + 2NO → 2NO₂, NO₂ + ^•OH_f → HNO₃), inhibiting the production of the byproducts of NO₂. This work is helpful for understanding the surface mechanism of photocatalytic NO_x oxidation and provides a new perspective for the development of highly efficient air purification systems.

Two-dimensional material-based functional aerogels for treating hazards in the environment: synthesis, functional tailoring, applications, and sustainability analysis

Environmental pollution is a global problem that endangers human health and ecological balance. As a new type of functional material, two-dimensional material (2DM)-based aerogel is one of the most promising candidates for pollutant detection and environmental remediation. The porous, network-like, interconnected three-dimensional (3D) structure of 2DM-based aerogels can not only preserve the characteristics of the original 2DMs, but also bring many distinct physical and chemical properties to offer abundant active sites for adsorbing and combining pollutants, thereby facilitating highly efficient monitoring and treatment of hazardous pollutants. In this review, the synthesis methods of 2DM aerogels and their broad environmental applications, including various sensors, adsorbents, and photocatalysts for the detection and treatment of pollutants, are summarized and discussed. In addition, the sustainability of 2DM aerogels compared to other water purification materials, such as activated carbon, 2DMs, and other aerogels are analyzed by the Sustainability Footprint method. According to the characteristics of different 2DMs, special focuses and perspectives are given on the adsorption properties of graphene, MXene, and boron nitride aerogels, as well as the sensing and photocatalytic properties of transition metal dichalcogenide/oxide and carbon nitride aerogels. This comprehensive work introduces the synthesis, modification, and functional tailoring strategies of different 2DM aerogels, as well as their unique characteristics of adsorption, photocatalysis, and recovery, which will be useful for the readers in various fields of materials science, nanotechnology, environmental science, bioanalysis, and others.

Photoenzymatic Catalytic Cascade System of a Pyromellitic Diimide/g-C3N4 Heterojunction to Efficiently Regenerate NADH for Highly Selective CO2 Reduction toward Formic Acid

Photocatalytic reduction of carbon dioxide (CO₂) holds great promise for both clean energy and environment protection. However, the low activity and poor selectivity of photocatalysts are the main bottlenecks. Herein, inspired by artificial photosynthesis and taking advantages of high efficiency and specificity of bioenzymes, we marry photo with enzyme to synergistically solve the above problems. A metal-free heterojunction of pyromellitic diimide/g-C₃N₄ (PDI/CN) with an excellent visible light response (λ < 660 nm) is fabricated for achieving a photoenzymatic catalytic cascade system, which efficiently regenerates nicotinamide adenine dinucleotide (NADH) and selectively reduces CO₂ to formic acid (HCOOH). The highest NADH yield of the PDI/CN hybrid achieved is 75%, and the HCOOH generation rate achieved is 1.269 mmol g^-1 h^-1 with nearly 100% selectivity, which is much higher than those of the reported materials. The excellent photocatalytic performance is attributed to the unique photoenzymatic catalytic cascade system, heterointerface effect, good conductivity, and a wide sunlight response range of the PDI/CN heterojunction. This work provides an efficient strategy and a corresponding photocatalyst for the directional conversion of CO₂ to HCOOH.

Review on application of perylene diimide (PDI)-based materials in environment: Pollutant detection and degradation

Environment pollution is getting serious and various poisonous contaminants with chemical durability, biotoxicity and bioaccumulation have been widespreadly discovered in municipal wastewaters and surface water. The detection and removal of pollutants show great significance for the protection of human health and other organisms. Due to its distinctive physical and chemical properties, perylene diimide (PDI) has received widespread attention from different research fields, especially in the area of environment. In this review, a comprehensive summary of the development of PDI-based materials in fluorescence detection and advanced oxidation technology for environment was introduced. Firstly, we chiefly presented the recent progress about the synthesis of PDI and PDI-based nanomaterials. Then, their application in fluorescence detection for environment was presented and categorized, principally including the detection of heavy metal ions, harmful anions and organic contaminants in the environment. In addition, the application of PDI and PDI-based materials in different advanced oxidation technologies for environment, such as photocatalysis, photoelectrocatalysis, Fenton and Fenton-like reaction and persulfate activation, was also summarized. At last, the challenges and future prospects of PDI-based materials in environmental applications were discussed. This review focuses on presenting the practical applications of PDI and PDI-based materials as fluorescent probes or catalysts (especially photocatalysts) in the detection of hazardous substances or catalytic elimination of organic contaminants. The contents are aimed at supplying the researchers with a deeper understanding of PDI and PDI-based materials and encouraging their further development in environmental applications.

CoOx @Co-NC Catalyst with Dual Active Centers for Enhanced Oxygen Evolution: Breaking Trade-Off of Particle Size and Metal Loading

Increasing the metal loading and downsizing the metal particle size are two effective ways to boost the electrochemical performance of catalysts. However, it is difficult to simultaneously increase the metal loading and reduce the particle size since isolated individual atoms are easy to aggregate into nanoparticles when increasing the metal loading. To tackle this contradiction, we report a bottom-up ligand-mediated strategy to facilely prepare ultrafine CoO_x nanoclusters anchored on a Co-N-containing carbon matrix (CoO_x @Co-NC). The co-exist of N and O atoms prevent Co atoms agglomerating into large particles and allowing the formation of ultrafine dispersed Co species with large Co loading (up to 20 wt.%). Since the relationship between ultrasmall size and large metal loading is well balanced, the CoO_x nanoclusters have no inhibitory effect, but facilitate the catalytic performance of Co-N₄ sites during OER process. Consequently, due to the synergistic effect of ultrafine CoO_x nanoclusters and Co-N₄ macrocycles, the as-synthesized CoO_x @Co-NC exhibit promising OER activity (η₁₀ =370 mV, Tafel plot=40 mV/dec), bettering than that of benchmark RuO₂ (η₁₀ =411 mV, Tafel plot=72 mV/dec). This ligand-mediated strategy to synthesize carbonaceous materials containing dual active centers with large metal loading is promising for developing active and stable catalysts for electrocatalytic applications.

Multi-functional 2D hybrid aerogels for gas absorption applications

Aerogels have attracted significant attention recently due to their ultra-light weight porous structure, mechanical robustness, high electrical conductivity, facile scalability and their use as gas and oil absorbers. Herein, we examine the multi-functional properties of hybrid aerogels consisting of reduced graphene oxide (rGO) integrated with hexagonal boron nitride (hBN) platelets. Using a freeze-drying approach, hybrid aerogels are fabricated by simple mixing with various volume fractions of hBN and rGO up to 0.5/0.5 ratio. The fabrication method is simple, cost effective, scalable and can be extended to other 2D materials combinations. The hybrid rGO/hBN aerogels (HAs) are mechanically robust and highly compressible with mechanical properties similar to those of the pure rGO aerogel. We show that the presence of hBN in the HAs enhances the gas absorption capacities of formaldehyde and water vapour up to ~ 7 and > 8 times, respectively, as compared to pure rGO aerogel. Moreover, the samples show good recoverability, making them highly efficient materials for gas absorption applications and for the protection of artefacts such as paintings in storage facilities. Finally, even in the presence of large quantity of insulating hBN, the HAs are electrically conductive, extending the potential application spectrum of the proposed hybrids to the field of electro-thermal actuators. The work proposed here paves the way for the design and production of novel 2D materials combinations with tailored multi-functionalities suited for a large variety of modern applications.

Supporting ultrathin “fish scale-like” BiOBr nanosheets on Bi6Mo2O15 sub-microwires for boosting photocatalytic performance

A BiOBr/Bi6Mo2O15 edge-on heterostructure with fast electron transport could improve interface conductivity and accelerate charge-separation efficiency.

Carbon-Graphitic Carbon Nitride Hybrids for Heterogeneous Photocatalysis

Polymeric graphitic carbon nitride (g-C₃ N₄ ) and various carbon materials have experienced a renaissance as viable alternates in photocatalysis due to their captivating metal-free features, favorable photoelectric properties, and economic adaptabilities. Although numerous efforts have focused on the integration of both materials with optimized photocatalytic performance in recent years, the direct parameters for this emerging enhancement are not fully summarized yet. Fully understanding the synergistic effects between g-C₃ N₄ and carbon materials on photocatalytic action is vital to further development of metal-free semiconductors in future studies. Here, recent advances of carbon/g-C₃ N₄ hybrids on various photocatalytic applications are reviewed. The dominant governing factors by inducing carbon into g-C₃ N₄ photocatalysts with involving photocatalytic mechanism are highlighted. Five typical carbon-induced enhancement effects are mainly discussed here, i.e., local electric modification, band structure tailoring, multiple charge carrier activation, chemical group functionalization, and abundant surface-modified engineering. Photocatalytic performance of carbon-induced g-C₃ N₄ photocatalysts for addressing directly both the renewable energy storage and environmental remediation is also summarized. Finally, perspectives and ongoing challenges encountered in the development of metal-free carbon-induced g-C₃ N₄ photocatalysts are presented.

The mechanisms and environmental implications of engineered nanoparticles dispersion

Dispersion of engineered nanoparticles (ENPs) has drawn special research attentions because the environmental behavior, risks, and applications of ENPs are greatly dependent on their dispersing status. This review summarizes the latest research progress of dispersion mechanisms, environmental applications in contaminants adsorption, and toxicity of ENPs dispersed in liquid and in solid matrix (3D-ENPs). Dispersion mechanisms of ENPs, including steric hindrance, electrostatic repulsion and "micelle wrapping" are well understood in single dispersing agent, however, the prediction of ENPs dispersion in real environments is not straightforward because of the diversity of structures, components, and properties of natural organic molecule mixtures. The adsorption characteristics, depending on the exposed surface areas in liquid, are significantly different between dispersed and aggregated ENPs. Comparing with the aggregated ENPs, the toxicity of dispersed ENPs is generally enhanced due to the increased uptake, released metal ions, carried contaminants, and induced ROS. 3D-ENPs not only inherit the excellent adsorption performance of ENPs dispersed in liquid, but also are beneficial to the separation and recycle from aqueous solutions due to their 3D rigid structures. However, the adsorption mechanisms as affected by environmental conditions are still unclear. Additionally, the potential risks of 3D-ENPs should be paid more attentions, with an emphasis on free radicals and stability of 3D structure.

Precursor-Engineering Coupled Microwave Molten-Salt Strategy Enhances Photocatalytic Hydrogen Evolution Performance of g-C3 N4 Nanostructures

A precursor-engineering strategy coupled with a microwave molten-salt process (PE-MWMS) is developed to synthesize graphitic carbon nitride (g-C₃ N₄ ) with an isotype triazine/heptazine-based g-C₃ N₄ heterojunction as a photocatalyst for the hydrogen evolution reaction (HER) under visible light illumination. Four hybrid precursor combinations-thiourea/melamine, thiourea/dicyandiamide, urea/melamine, and urea/dicyandiamide-are used to synthesize g-C₃ N₄ heterojunctions by the PE-MWMS process. Control experiments indicate that the precursor components and microwave treatment have a great effect on the HER performance of the g-C₃ N₄ samples. Samples synthesized with the optimal molar ratios of thiourea/melamine (2:1), thiourea/dicyandiamide (2:1), urea/melamine (3:1), and urea/dicyandiamide (3:1), exhibit the highest HER rates of 3135, 2519, 2844, and 2565 μmol g^-1  h^-1 , respectively. The amounts of heptazine and triazine units in the g-C₃ N₄ samples can be easily adjusted by changing the ratios of the hybrid precursors and play a decisive role in improving the photocatalytic HER activity. Because of the unique composition and microstructure, the efficient separation of electron-hole pairs, the broadened photo-absorption edges, and the narrowed band gaps, the as-obtained triazine/heptazine-based g-C₃ N₄ nanostructures exhibit promising activity for HER application.

3D graphene-based gel photocatalysts for environmental pollutants degradation

Enormous research interest is devoted to fabricating three-dimensional graphene-based gels (3D GBGs) toward improved conversion of solar energy by virtue of the intrinsic properties of single graphene and 3D porous structure characteristics. Here, this concise minireview is primarily focused on the recent progress on applications of 3D GBGs, including aerogels and hydrogels, in photocatalytic degradation of pollutants from water and air, such as organic pollutants, heavy metal ions, bacteria and gaseous pollutants. In particular, the preponderances of 3D GBG photocatalysts for environmental pollutants degradation have been elaborated. Furthermore, in addition to discussing opportunities offered by 3D GBG composite photocatalysts, we also describe the existing problems and the future direction of 3D GBG materials in this burgeoning research area. It is hoped that this review could spur multidisciplinary research interest for advancing the rational utilization of 3D GBGs for practical applications in environmental remediation.

ZIF-67-Derived 3D Hollow Mesoporous Crystalline Co3 O4 Wrapped by 2D g-C3 N4 Nanosheets for Photocatalytic Removal of Nitric Oxide

ZIF-67-derived 3D hollow mesoporous crystalline Co₃ O₄ wrapped by 2D graphitic carbon nitride (g-C₃ N₄ ) nanosheets are prepared by low temperature annealing, and are used for the photocatalytic oxidation of nitric oxide (NO) at a concentration of 600 ppb. The p-n heterojunction between Co₃ O₄ and g-C₃ N₄ forms a spatial conductive network frame and results in a broad visible light response range. The hollow mesoporous structure of Co₃ O₄ contributes to the circulation and adsorption of NO, and the large specific surface area exposes abundant active sites for the reaction of active species. A maximum NO degradation efficiency of 57% is achieved by adjusting the mass of the Co₃ O₄ precursor. Cycling tests and X-ray diffraction indicate the high stability and recyclability of the composite, making it promising in environmental purification applications.

Gas-Phase Photoelectrocatalysis for Breaking Down Nitric Oxide

Photoelectrocatalysis (PEC) produces high-efficiency electron-hole separation by applying a bias voltage between semiconductor-based electrodes to achieve high photocatalytic reaction rates. However, using PEC to treat polluted gas in a gas-phase reaction is difficult because of the lack of a conductive medium. Herein, we report an efficient PEC system to oxidize NO gas by using parallel photoactive composites (TiO₂ nanoribbons-carbon nanotubes) coated on stainless-steel mesh as photoanodes in a gas-phase chamber and Pt foil as the working electrode in a liquid-phase auxiliary cell. Carbon nanotubes (CNTs) were utilized as conductive scaffolds to enhance the interaction between TiO₂ and stainless-steel skeletons for accelerated photogenerated electron transfer. Such a PEC system exhibited super-high performance for the treatment of indoor NO gas (550 ppb) with high selectivity for nitrate under UV-light irradiation owing to the conductive, intertwined network structure of the photoanode, fast photocarrier separation, and longer photogenerated hole lifetime. The photogenerated holes were proven to be the most important active sites for directly driving PEC oxidation of indoor NO gas, even in the absence of water vapor. This work created an efficient PEC air-purification filter for treating indoor polluted air under ambient conditions.

Recent Advances in Carbonaceous Photocatalysts with Enhanced Photocatalytic Performances: A Mini Review

Photocatalytic processes based on various semiconductors have been widely utilized in different applications, with great potential for use in environmental pollution remediation and sustainable energy generation. However, critical issues, including low light adsorption capability, wide energy bandgap, and unsatisfactory physicochemical stability still seriously limit the practical applications of photocatalysts. As a solution, the introduction of carbonaceous materials with different structures and properties into a photocatalyst system to further increase the activity has attracted much research attention. This mini review surveys the related literatures and highlights recent progress in the development of carbonaceous photocatalysts, which include various metal semiconductors with activated carbon, carbon dots, carbon nanotubes/nanofibers, graphene, fullerene, and carbon sponges/aerogels. Moreover, graphitic carbon nitride is also discussed as a carbon-rich and metal-free photocatalyst. The recently developed synthesis strategies and proposed mechanisms underlying the photocatalytic activity enhancement for different applications are summarized and discussed. Finally, ongoing challenges and the developmental direction for carbonaceous photocatalysts are proposed.

Photocatalytic reduction of Uranium(VI) under visible light with Sn-doped In2S3 microspheres

Visible light-driven conversion of soluble U(VI) to slightly soluble U(IV) has been regarded as a efficient and environmentally friendly technology to deal with uranium containing wastewater. In this paper, we attempted to use photocatalytic technology to reduction U(VI) from aqueous solution by constructing a highly efficient photocatalysts. The novel Sn-doped In₂S₃ microspheres photocatalyst were synthesized for the first time by a simple hydrothermal method, and characterized with various analytical and spectroscopic techniques to determine their structural, morphological, compositional, optical and photocatalytic properties. In determination of photocatalytic activity, the results showed that all Sn-doped In₂S₃ samples exhibited greater photocatalytic performance in reduction of U(VI) under visible light than the pure In₂S₃. The optimum SnIn₂S₃ photocatalyst with Sn:In molar ratio of 1:4.8 (SnIn₂S₃) had the highest photocatalytic performance (95% reduction efficiency within 40 min irradiation time), which was approximately 15.60 times faster than that of pure In₂S₃. The enhanced photocatalytic activity of the optimum SnIn₂S₃ was largely ascribed to the higher specific surface area, red-shift in the absorption band, the efficient separation of photogenerated electron-hole pairs (e^-/h⁺) and the narrowed band gap with an up shifting of valence band, conduction band potentials. In addition the optimum SnIn₂S₃ photocatalyst exhibited a good recyclability and stability during the repetitive experiments. Finally, the possible active species and the possible mechanism on basis of the experimental results were discussed in detail.