Visible-light Catalyst Research Articles

Cu/S Co-anchoring junction boosted the photogenerated carrier separation efficiency in g-C3N5 for enhanced H2 evolution

C3N5 is emerging as an important visible light catalyst because of its narrow band gap, nontoxicity and thermal stability. Herein, sulfur-doped g-C3N5 (SCN) was prepared by copolymerization of thioacetamide (TAA) and 3-amino-1,2,4-triazole (3-AT). Then copper nanoparticles (Cu NPs) were anchored onto the SCN framework, resulting in the formation of Cu/SCN. It was found that the average H2 production rate of SCN and Cu/SCN was 0.76 and 1.34 mmol g−1 h−1, which was much higher than that of C3N5, respectively. Acting as a new active spots, sulfur doping effectively reduces the band gap of g-C3N5, and the formation of S-Cu bonds further creates an efficient electron transport pathway. As a result, Cu/SCN possesses a broader visible light absorption spectrum, stronger reduction capability, and greater efficiency in photo-induced carrier separation and transfer. Therefore, this work introduces a novel strategy for design of high efficiency photocatalytic H2 evolution carbon nitride through non-noble metal and sulfur anchoring junction.

Unveiling new insights into photocatalytic enhancement of p-n BiVO4-OV/NiMoO4 Heterojunctions through oxygen defect engineering

The development of efficient and stable photocatalysts holds vital importance in the fast and effective removal of toxic contaminants from wastewater. In this study, novel 1D/2D BiVO4-OV/NiMoO4 hybrid with enriched oxygen vacancies (BiVO4-OV/NiMoO4) were successfully synthesized by using one step hydrothermal synthesis route. Utilizing the p-n heterojunction and oxygen vacancies, the optimized BiVO4-OV/NiMoO4 composite exhibited exceptional photocatalytic efficiency, achieving a photocatalytic degradation efficiency of 92 % for rhodamine B (RhB) under visible light irradiation within 60 min. The apparent rate constant of value of optimized BiVO4-OV/NiMoO4 composite is 0.02864 min−1, exceeding those of BiVO4 and NiMoO4 by 4.4 times and 5.5 times, respectively. The photocatalytic mechanism and degradation pathways of RhB were investigated through active species trapping experiment. Remarkably, optimized BiVO4-OV/NiMoO4 hybrid demonstrated high stability and recyclability. This study on the development of highly efficient visible-light catalysts through synergistic defect and heterojunction engineering, offering a promising approach for organic pollutant degradation.

In Situ Driven Formation of Anatase/Brookite/Rutile Heterojunction N/TiO2 Nanocrystals as Sustainable Visible-Light Catalysts.

Visible-light active anatase/brookite/rutile (A/B/R) ternary N-doped titania (N/TiO2) crystals are successfully prepared by a facile sol-gel method using titanium butoxide and benign N-dopant source, guanidinium chloride. Systematically varying the aging time (1, 4, 8, and 12 d), its influence on physicochemical properties of as-obtained spherical heterojunction nanomaterials is studied. Detailed characterizations confirm that a substantial amount of anatase (88% to 50%) is transformed to rutile (2% to 38%) via intermediate brookite phase (9% to 25%) as the function of aging time; not only the A/B/R phase content of the samples is tuned by sol-gel aging time of the precursors solution but also their optical-response and methylene blue photocatalytic properties are profoundly dictated. Notably under visible-light irradiation, the photostable rutile rich mesoporous A/B/R triphasic N/TiO2 (50% A, 12% B, 38% R) aged for 12 d demonstrates higher degradation activity (97%) with a faster degradation rate (0.033 min-1) than both lesser aged N/TiO2 and undoped titania. This enhancement is attributed to the synergistic effect of interstitial-N-doping and optimal A/B/R interfacial charge transfer that leads to higher light absorption, lower bandgap energy and well-separated charge carriers. The current work provides a new perspective for designing highly active visible-light heterostructure nanomaterials with controllable phase composition.

Multiple strategies enhance visible-light photocatalytic degradation levofloxacin of Fe-doped MOF/AgCl Z-scheme heterojunction composites based on pyrazole carboxylic ligand

The construction of visible-light catalysts to degrade water pollutants is significant in environmental governance and solar energy conversion. In this work, a novel Zn-MOF with unsaturated coordination sites was constructed using 1-(Carboxymethyl)-pyrazole-4-carboxylic acid as the organic ligand. Its crystal structure was studied through single crystal X-ray diffraction. To enhance visible light catalytic performance, ZnFe-MOF/AgCl-x Z-scheme heterojunction composites were constructed. The optimized ZnFe-MOF/AgCl-50 material exhibits excellent photocatalytic performance, which can degrade 90.33 % of levofloxacin in 21 min. The results indicate that Fe doping and the construction of the ZnFe-MOF/AgCl-x Z-scheme heterojunction not only broaden the responsive range to visible light, but also effectively promote the internal and interfacial charges transfer efficiency, leading to a superior catalytic performance. In addition, the Ag nanoparticles (NPs) generated during the photocatalytic process can serve as a bridge, achieving rapid charge transfer in Z-scheme heterojunction. This work can offer an innovative perspective for the development of novel and efficient MOF-based Z-scheme heterojunction photocatalysts for wastewater treatment applications.

Construction of a Wood Nanofiber-Bismuth Halide Photocatalyst and Catalytic Degradation Performance of Tetracycline from Aqueous Solutions.

Nanostructured bismuth oxide bromide (BiOBr) has attracted considerable attention as a visible light catalyst. However, its photocatalytic degradation efficiency is limited by its low specific surface area. In this study, a solvothermal approach was employed to synthesize BiOBr, which was subsequently loaded onto cellulose nanofibers (CNFs) to obtain a bismuth halide composite catalyst. The performance of this catalyst in the removal of refractory organic pollutants such as tetracycline (TC) from solutions under visible light excitation was examined. Our results indicate that BiOBr/CNF effectively removes TC from the solution under light conditions. At a catalyst dosage of 100 mg/L, the removal efficiency for TC (with an initial concentration of 100 mg/L) was 94.2%. This study elucidates the relationship between the microstructure of BiOBr/CNF composite catalysts and their improved photocatalytic activity, offering a new method for effectively removing pollutants from water.

Efficient Photocatalytic System based on Schiff‐Base Type Hybrid Polymers for Energy Conversion and Water Treatment

AbstractIn this contribution, a new Schiff‐base hybrid cross‐linked polymer (TFPT‐SHCP) derived from triazine derivatives and silsesquioxanes was developed, and its photocatalytic performance was systematically investigated. Compared with traditional organic Schiff base catalysts, in TFPT‐SHCP, organic inorganic hybrid silsesquioxanes monomers at the molecular level can serve as a sturdy host backbone, bringing structural ultrastability to the final material. And their excellent strength and durability make them have good application prospects in water treatment. Furthermore, the introduction of triazine derivatives with excellent photoelectric performance and the construction of −C=N‐ result in excellent photocatalytic performance of TFPT‐SHCP. The as‐prepared TFPT‐SHCP exhibits excellent degradation capacity of various organic pollutants under visible light catalysis, with degradation rate constants for Congo Red (CR), rhodamine B (RB) and tetracycline hydrochloride (TH) reaching 0.302 min−1, 0.121 min−1, 0.161 min−1, respectively. Under simulated outdoor conditions, dye solutions with concentrations up to 500 ppm can be degraded to complete decolorization within 5 weeks. This work demonstrates the enormous potential of POSS‐based Schiff base materials as a platform for visible light catalysts, paving the way for the pre design and functionalization of related materials in the future.

Indoor-Light-Activated Blue TiO2-Molecule-WO3 Visible Photocatalyst for Antibacterial Performance against Escherichia coli.

Currently used visible light catalysts either operate with high-power light sources or require prolonged periods of time for catalytic reactions. This presents a limitation regarding facile application in indoor environments and spaces frequented by the public. Furthermore, this gives rise to elevated power consumption. Here, we enhance photocatalytic performance with blue TiO2 and WO3 complexes covalently coupled through an organic molecule, 3-mercaptopropionic acid, under indoor light. Antibacterial experiments against 108 CFU/mL Escherichia coli (E. coli) suspensions were conducted under indoor light exposure conditions. They showed a sterilization effect of almost 90% within 70 min and nearly 100% after 110 min. The complex generates reactive oxygen species (ROS), such as •OH and O2•-, under natural air conditions. We also showed that h+ and •OH are important for sterilizing E. coli using common scavengers. This research highlights the potential of these complexes to generate ROS, effectively playing a crucial role in antibacterial effects under indoor light.

Photo-induced in-situ synthesis of Cu2O@C nanocomposite for efficient photocatalytic evolution of hydrogen

Cuprous oxide (Cu2O) is an ideal visible light catalyst owing to its narrow band gap, environmental benignity and abundant storage; however, the fast recombination of photogenerated charge carriers and poor stability of Cu2O has impeded its application in photocatalysis. Herein, we demonstrate that Cu2O@C nanocomposite can spontaneously evolve from a methanol aqueous solution containing cupric ions under the induction of irradiation. Compared with the traditional carbon coating method, the Cu2O@C nanocomposite obtained by the photo-induced in-situ synthesis can reserve superior original characteristics of the semiconductor under mild reaction conditions, promote the charge transfer and enhance the separation efficiency of charge carriers; in addition, the carbon shells can also effectively prevent Cu2O from photo-corrosion. As a result, the Cu2O@C nanocomposite exhibits excellent photocatalytic activity in the hydrogen evolution in comparison with the Cu2O particles; the H2 evolution rate over the Cu2O@C nanocomposite reaches 1.28 mmol/(g·h) under visible light, compared with the value of 0.065 mmol/(g·h) over Cu2O. Moreover, the Cu2O@C nanocomposite displays good cycle stability, viz., without any deactivation in the catalytic activity after five cycles.

Visible light-driven Cl-g-C3N4 activated peroxydisulfate process for TMP efficient degradation in a wide pH range

A narrow pH-applicability range can impact the actual treatment efficiency of AOPs, so the application of a wide pH range in AOP technology has garnered significant attention. In this study, the Cl-doped g-C3N4 as a visible light catalyst to activate the peroxydisulfate (PDS) process, named Vis/Cl-g-C3N4/PDS, was developed for trimethoprim (TMP) degradation in a wide pH range of 3–11. Results show that the Vis/Cl-g-C3N4/PDS process exhibited degradation efficiencies for TMP that were 1.39 times and 7.74 times higher than those of the Vis/Cl-g-C3N4 process and the Vis/g-C3N4 process, respectively. The Vis/Cl-g-C3N4/PDS process perfectly achieved degradation rates of over 98 % for TMP within a wide pH range of 3–11. It concluded that the high efficiency of the Vis/Cl-g-C3N4/PDS process in degrading TMP over a wide pH range was caused by the two co-existing reactive oxygen species (ROS) generation mechanism pathways: the photocatalytic activation of PDS and the light-assisted hydrolysis of PDS. Moreover, after 3 h of illumination in the Vis/Cl-g-C3N4/PDS process, a degradation range of 85.7 %–97.8 % was demonstrated in various real water matrices including of tap water, secondary sedimentation tank effluent, surface water, and aquaculture water. This study provided practical significance for the practical application of AOPs in water environmental pollution control.

G-C3N4 modified with non-precious metal Al with LSPR as an efficient visible light catalyst.

The issue of water pollution has emerged as a formidable challenge, prompting a pressing need for solutions. The utilization of metal nanoparticles with surface plasmon resonance and semiconductor composite photocatalysts is regarded as a highly effective approach to solve this problem. g-C3N4 is an effective catalyst for the degradation of organic pollutants. Its photocatalytic performance is usually enhanced by the use of the noble metal Au Ag. However, the high cost of these materials limits their application. In this study, we present the synthesis of Al NPs/g-C3N4 nanocomposites using the bridging effect of ligands. The characterized of transmission electron microscopy (TEM), X-ray diffractometer (XRD) and ultraviolet-visible spectroscopy (UV-Vis) proved that Al NPs/g-C3N4 with a wider light absorption range were successfully synthesized. The effects of ligands, (glutathione (GSH), glutamic acid (GAG), and cysteine (CYS)), Al diameter (40 to 200 nm) and the ratio of Al to g-C3N4 (1:1 to 5:1) on the photocatalytic degradation of methylene blue (MB) by Al NPs/g-C3N4 were also evaluated. The results showed that the optimum degradation efficiency of Al NPs/g-C3N4 for MB at 5 mg/L reached 100% within 60 min, which was 11 times higher than that of pure g-C3N4. The principal analysis of Al enhancing the photocatalytic performance of g-C3N4 was studied through transient photocurrent spectroscopy (TPC), electrochemical impedance spectroscopy (EIS), and steady-state transient fluorescence spectroscopy (PL). The results confirmed that hot carriers generated by localized surface plasmon resonance (LSPR) of Al nanoparticles increase the carrier concentration. In addition, the Schottky barrier generated by Al and g-C3N4 could also improve the carrier separation rate and increase the carrier lifetime. This work is expected to solve the problem of organic wastewater treatment and lay the foundation for subsequent research on photocatalysis.

Homogeneous catalysis and heterogeneous recovery: Thermo-responsive copolymer visible light catalyst with phthalocyanine as side groups

Metal phthalocyanines (MPcs) have attracted more and more attention in recent years for the catalytic degradation of pollutants in water driven by visible light. However, they are easy to aggregate in the aqueous phase and difficult to recycle, which seriously limits their photocatalytic activity and applicability. Introducing phthalocyanine into polymers may be an effective way to solve the above problems. Herein, three kinds of copolymers PNIPAMx-co-PDUPcZny with different molecular weights and monomer ratios were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization, with S-1-dodecyl-S′-(α,α’-dimethyl-α”-acetic acid)trithiocarbonate (DDMAT) as chain transfer agent, 3-undecenamide-9(10),16(17),23(24)-decyloxy‑zinc phthalocyanine (DUPcZn) and N-isopropyl acrylamide (NIPAM) as monomers, 2,2′-azobis(2-methylpropionitrile) (AIBN) as initiator. The polymerization process shows the characteristics of living polymerization, and the polymer dispersity index (PDI) values are <1.1. The three copolymers exhibit obvious thermo-responsive characteristics and the lower critical solution temperatures (LCSTs) are between 32.7 °C and 33.1 °C. The photocatalytic activity of the copolymers was evaluated by using 1,5-dihydroxynaphthalene (DHN) and Cr(VI) as model pollutants. It was found that the three copolymers had photocatalytic oxidation performance for DHN and photocatalytic reduction performance for Cr(VI), and their photocatalytic property was affected by the pH of the model pollutant solution and the catalytic temperature. Among them, PNIPAM57-co-PDUPcZn7 exhibit a photocatalytic oxidation rate of 93.0% for DHN and the photocatalytic reduction rate of 70.0% for Cr(VI), respectively, under the visible light irradiation for 120 min at pH = 5 and 32 °C. More importantly, the homogeneous catalysis and heterogeneous recovery are achieved in the catalytic process through simple temperature regulation. In addition, the copolymers exhibited excellent chemical stability and reusability after three cycles. Finally, O21/e− was determined to be the active species that plays a crucial role in the photocatalytic oxidation/reduction process, upon which a possible photocatalytic mechanism was proposed. This research provides a promising strategy for the synthesis of environmentally friendly visible light catalysts for the sewage (waste) water treatment.

Au decorated chemically exfoliated g-C3N4 as highly efficient visible light catalyst for hydrogen production

The demand for photocatalytic hydrogen production through water splitting is continuously increasing as the world is seeking cleaner and sustainable energy solutions. Herein, we report a comparative study of the as-fabricated Bulk g-C3N4 (BCN), chemically exfoliated g-C3N4 (ECN) and Au-decorated chemically exfoliated g-C3N4 (Au/ECN) photocatalysts for visible light-driven catalytic hydrogen production. To understand the structural, morphological, chemical, and electronic properties of the as-fabricated photocatalysts, XRD, TEM, Raman, PL, XPS, FTIR, UV and EPR analysis was performed. The as-prepared Au/ECN photocatalyst revealed exceptional visible light catalytic performance by producing 410 μmol·g−1 of hydrogen, which is 27.3- and 9.3-fold enhanced compared to those of the CN (15 μmol·g−1) and ECN (44 μmol·g−1) photocatalysts, respectively. This improved visible light-driven catalytic performance of the Au/ECN photocatalyst for hydrogen production is due to the enhanced specific surface area via the chemically exfoliated layered sheets, promoted light absorption due to the decrease in band gap via the effect of surface plasmon resonance attributable to decorated Au nanoparticles, and efficient separation of charge carriers at the interfacial contact. The photocatalytic recyclable experiments indicate excellent stability of the Au/ECN photocatalyst for H2 evolution. These findings reveal the effect of chemical exfoliation and Au decorating on the catalytic efficiency of g-C3N4-based photocatalysts, revealing potential functions for green hydrogen production under the standard visible light illumination.

NH2-MIL-125-Derived N-Doped TiO2@C Visible Light Catalyst for Wastewater Treatment.

The utilization of titanium dioxide (TiO2) as a photocatalyst for the treatment of wastewater has attracted significant attention in the environmental field. Herein, we prepared an NH2-MIL-125-derived N-doped TiO2@C Visible Light Catalyst through an in situ calcination method. The nitrogen element in the organic connector was released through calcination, simultaneously doping into the sample, thereby enhancing its spectral response to cover the visible region. The as-prepared N-doped TiO2@C catalyst exhibited a preserved cage structure even after calcination, thereby alleviating the optical shielding effect and further augmenting its photocatalytic performance by increasing the reaction sites between the catalyst and pollutants. The calcination time of the N-doped TiO2@C-450 °C catalyst was optimized to achieve a balance between the TiO2 content and nitrogen doping level, ensuring efficient degradation rates for basic fuchsin (99.7%), Rhodamine B (89.9%) and tetracycline hydrochloride (93%) within 90 min. Thus, this study presents a feasible strategy for the efficient degradation of pollutants under visible light.

Bimetallic Porphyrin-Based Metal-Organic Framework as a Superior Photocatalyst for Enhanced Photocatalytic Hydrogen Production.

The meaningful and rational engineering of porphyrin-based catalysts with multimetallic active sites is very attractive toward photocatalytic hydrogen generation from water decomposition. Herein, three metal organic frameworks (MOFs) based on meso-tetrakis(4-carboxylphenyl)porphyrin (TCPP) were successfully constructed under solvothermal conditions. As a novel architectured photocatalyst (triclinic, C48H29N4O10PdYb), Pd/Yb-PMOF manifested diverse metal active sites, suitable bandgap positions, prominent visible light-collecting capacity, excellent carrier transfer efficiency, and obvious synergistic effect between ytterbium and palladium ions. Consequently, such a bimetallic MOF exhibited strengthened photocatalytic hydrogen evolution performance. Concretely, its hydrogen generation efficiency was up to 3196.42 μmol g-1 h-1 with 2 wt % Pt as a cocatalyst under visible light illumination. Our work demonstrates a promising strategy for highly efficient visible-light catalysts based on bimetallic-trimmed porphyrin MOFs.

Enhanced removal of perfluoroalkyl substances using MMO-TiO2 visible light photocatalyst

Exploration of easily produced visible light photocatalysts is still necessary. Thus, this study investigated the catalytic performance of a mixed metal oxide-titanium dioxide (MMO-TiO2) to remove perfluorooctanoic acid (PFOA), a typical and harmful perfluoroalkyl substance, under visible light conditions. Analysis of degradation efficiencies revealed that MMO-TiO2 exhibited a remarkable removal efficiency of 95.99 ± 1.49 %, surpassing other catalysts, including TiO2, ZnAl, MMO, and ZnAl-TiO2. MMO-TiO2, derived from ZnAl-TiO2 calcination, displayed a 5.66-fold higher apparent degradation rate constant (1.07 × 10−2 min−1) compared to ZnAl-TiO2 (1.89 × 10−3 min−1). These materials were characterized via X-ray powder diffractometry, Fourier transform infrared-attenuated total reflectance, N2 adsorption-desorption analysis, and field emission-scanning electron microscopy. Results revealed that O2•- radicals play a pivotal role as the predominant species that mediate PFOA removal. Comparative experiments using probe compounds confirmed increased O2•- production during MMO-TiO2 photoreaction under visible light. In addition, this study explored the effect of operational parameters, such as catalyst dose, initial PFOA concentration, solution pH, and water matrices on the photocatalytic removal process. These findings provide insight into the removal of PFOA using MMO-TiO2, highlighting the potential of this visible light catalyst for the eco-friendly removal of persistent organic pollutants in aquatic systems.

Synthesis of Graphene Based Graphitic Carbon Nitride Hybrid Nanocomposite Photocatalysts for Hydrogen Generation: A Mini Review

The discovery of visible active photocatalysts for H2 evolution via water splitting is the most awaited and critical goal of many researchers in recent years. Novel polymeric graphitic carbon nitride (GCN/g-CN) has emerged as a versatile material which has attracted the scientific community and industrialist because of its distinctiveness and outstanding electronic properties. g-CN is a metal free semiconductor as well as non-toxic, biodegradable polymeric material with low band gap energy which makes it a promising candidate as a photocatalyst and its efficiency as a catalyst can be modified by forming a hybrid nanocomposite with other semiconducting materials. Reduced graphene oxide, another metal free 2D material is a very good choice for this purpose. This review is an outlook for the synthesis processes and various properties of both g-CN and graphene. Further, it gives the approaches attempted towards the modifications required and done towards the development of a metal-free nano-hybrid material which is cost-effective, eco-friendly, and highly active visible light catalyst for the water- splitting process.

Construction of a porous pyrite cinder-supported Mn-doped BiFeO3 composite photocatalyst: Confined-space strategy, structure, and visible-light catalytic degradation toward ciprofloxacin

A series of novel confined visible-light catalysts, namely, Mn-doped BiFeO3 (MBFO) composite photocatalyst anchored on porous residue pyrite cinder (PR-PyC) after partial Fe extraction (PR-PyC/MBFO-φ, φ refers to the doped amount of Mn), was successfully constructed via confined-space strategy using the Fe extracted from PyC as Fe source for BiFeO3 (BFO) and the PR-PyC as the template and structure regulator for MBFO generation. The resulting PR-PyC/MBFO-5% is composed of relatively uniform nanoparticles anchored in the channels of PR-PyC matrix and interparticle interstices and has a specific surface area of 14.18 m2/g, an average pore size of 37.76 nm, and a pore volume 0.13 cm3/g. It has a type-II heterojunction with a band gap energy (Eg) of 1.95 eV and exhibits high visible-light catalytic degradation activity toward ciprofloxacin (CIP) and excellent recyclability. The CIP degradation rate of PR-PyC/MBFO-5% reached 96.41% with an apparent reaction rate constant kapp of 0.0265 min−1 under visible-light irradiation for 120 min, and the corresponding mineralization rate reached 77.42%. The active species produced during photocatalysis were h+ and •OH, in which h+ plays a major role. The doping of 5% Mn can effectively regulate the energy band structure and heterojunction type and the use of an appropriate amount of PR-PyC can effectively guide and regulate the structure and morphology of the as-prepared catalyst. This study presents an effective confined-space strategy for fabricating innovative high-efficiency photocatalysts for antibiotic degradation, thereby paving the way for the valuable resource utilization of PyC.

V2C MXene–modified g-C3N4 for enhanced visible-light photocatalytic activity

Increasing the efficiency of charge transfer and separation efficiency of photogenerated carriers are still the main challenges in the field of semiconductor-based photocatalysts. Herein, we synthesized g-C3N4@V2C MXene photocatalyst by modifying g-C3N4 using V2C MXene. The prepared photocatalyst exhibited outstanding photocatalytic performance under visible light. The degradation efficiency of methyl orange by g-C3N4@V2C MXene photocatalyst was as high as 94.5%, which is 1.56 times higher than that by g-C3N4. This was attributed to the V2C MXene inhibiting the rapid recombination of photogenerated carriers and facilitating rapid transfer of photogenerated electrons (e−) from g-C3N4 to MXene. Moreover, g-C3N4@V2C MXene photocatalyst showed good cycling stability. The photocatalytic performance was higher than 85% after three cycles. Experiments to capture free radicals revealed that superoxide radicals (·O2−) are the main contributors to the photocatalytic activity. Thus, the proposed g-C3N4@V2C MXene photocatalyst is a promising visible-light catalyst.

Boosting photocatalytic performance of silver phosphate via coupling with P-doped carbon for amoxicillin degradation

Amoxicillin (AMX) could result in risks to ecosystems and organisms in the environment, and photocatalysis is regarded as an effective technology for catalytic degradation of antibiotics. In this study, for the first time, we doped element P into ultra-thin three-dimensional carbon nanosheets to prepare P-doped carbon materials (PCs), and then coupled them with Ag3PO4 to prepare Ag3PO4 @PC composites successfully. The novel composite catalyst was used for photocatalytic degradation of AMX in aqueous solution. Results showed that the photocatalytic performance and cycle stability of Ag3PO4 @PC were much better than that of Ag3PO4 monomer. Under visible light conditions, the degradation efficiency of AMX by the composite catalyst under 3 min of light irradiation could reach 100%, and the corresponding apparent rate constant of AMX degradation was 0.0251 s−1. The DFT calculation results indicated that there was a large built-in potential well at the interface between PC and Ag3PO4, which can effectively reduce the internal recombination of photogenerated electron-hole pairs and improve the photocatalytic performance of the composite catalyst. This study provides an efficient visible light catalyst, and could be referred for appropriate design of innovative visible light photocatalysts.

Uranyl Polyoxotungstate Cluster for Visible-Light-Driven Heterogeneous C-H Selective Fluorination.

The selective fluorination of C-H bonds at room temperature using heterogeneous visible-light catalysts is both interesting and challenging. Herein, we present the heterogeneous sandwich-type structure uranyl-polyoxotungstate cluster Na17{Na@[(SbW9O33)2(UO2)6(PO3OH)6]}·46H2O (denoted as U6P6) to regulate the selective fluorination of the C-H bond under visible light and room temperature. This is the first report in which uranyl participates in the fluorination reaction in the form of an insoluble substance. U6P6 is capable of the effective selective fluorination of cycloalkanes and the recyclability of the photocatalyst due to the synergistic effect of multiple uranyl (UO2)2+ and the insolubility of organic reagents of polyoxotungstate. In situ electron paramagnetic resonance spectroscopy captured the generation of cycloalkane radicals during the photoreaction, confirming the mechanism of direct hydrogen atom transfer.