Rapid Charge Recombination Research Articles

Boosting the Photocatalytic H2 Evolution and Benzylamine Oxidation using 2D/1D g-C3N4/TiO2 Nanoheterojunction.

The present research aims at the elevation of solar-to-chemical energy conversion with extortionate performance and sustainability. The nanostructured materials are revolutionizing the water splitting technology into decoupled hydrogen with simultaneous value-added organic chemical production. Yet, the bottleneck in semiconductor photocatalysis is rapid charge recombination and sluggish reaction kinetics. Herein, we demonstrate an efficient and non-noble metal-based catalyst for successful redox reaction with a theoretical modeling through density functional theory (DFT) study. Implementing this robust approach on 2D/1D ultrathin g-C3N4 nanosheets and TiO2 nanowires heterojunction, we achieved H2 production of 5.1 mmol g-1 h-1 with apparent quantum efficiency of 7.8% under visible light illumination and 93% of benzylamine conversion to N-benzylidene benzylamine in situ. The interface of 2D g-C3N4 nanosheets and 1D nanowires provide ample active sites and extends the visible light absorption with requisite band edge position for the separation of photoinduced charge carriers with superior stability. The electronic properties, band structure, and stability of the heterojunction are further investigated via DFT calculations which corroborate the experimental results and in good agreement for the enhanced activity of the heterojunction.

Triptycene incorporated carbon nitride based donor-acceptor conjugated polymers with superior visible-light photocatalytic activities

Polymeric carbon nitride (CN) has evoked considerable attention in photocatalysis, however, its π-deficiency conjugated frameworks engendering weak visible-light absorption and rapid charge recombination hinder the practical utilizations. Herein, a novel donor–acceptor (D-A) conjugated polymer based on triptycene incorporated carbon nitride (T-CN) has been facilely prepared by thermal copolymerization of melamine and 2,6,14-triaminotriptycene. Combined with the density functional theory (DFT) calculations, it is found that the formation of intramolecular charge transfer and the extended π-conjugative effect in the D-A structure contribute to a broadened light-harvesting spectral range, a higher charge separation/transfer efficiency and more active sites of T-CN for photoredox reactions. The T-CN catalyst accomplished superior visible-light photocatalytic performance in both hydrogen evolving and carbon dioxide reduction. The optimal T-CN catalyst exhibited the highest hydrogen evolution rate of 80.9 ± 1.3 μmol·h−1 and carbon monoxide production rate of 8.1 ± 0.2 μmol·h−1, which are ca. 8-fold and 20-fold of bulk CN, respectively. The convenient strategy of constructing D-A conjugated structure opens up a new intriguing avenue toward the rational creation of efficient polymeric nanomaterials for versatile applications of solar fuel production.

Perylene diimide growth on both sides of carbon nanotubes for remarkably boosted photocatalytic degradation of diclofenac

Perylene diimide and its derivatives are promising photocatalysts for clean and efficient production, but their practical application in the field of photocatalysis is still limited by the rapid photogenerated charge recombination. In this work, the confined photocatalysts were synthesized by using a gas-phase self-assembly method and comparing the morphology and photocatalytic properties of different photocatalysts after the confinement of carbon nanotubes. The confinement effect of carbon nanotubes acts to stabilize perylene diimide. Electrostatic interaction formed by a wide range of dispersion forces is dominant in the process of stabilization. Benefitting from the three-dimensional electron transfer pathway formed by the conjugation of perylene diimide with a large number of π electrons to the carbon nanotubes plane, the confined photocatalyst shows the pseudo-first-order kinetic constant k of 1.106 h−1 for the photocatalytic degradation of diclofenac under light, which is 6.11 times higher than that of perylene diimide. The electron transfer created an internal electric field at the interface from carbon nanotubes to perylene diimide, which greatly accelerated the separation of photogenerated electron-hole pairs and improved the photocatalytic activity. This study further expands the applicability of perylene diimide in the field of photocatalysis and provides a new approach for water environment treatment.

Precise interface modulation cascade enables unidirectional charge transport

Maneuvering spatial photo-induced charge modulation/separation over semiconductor-based photocatalysts represents an enduring challenge in solar-powered photoredox catalysis, but suffers from sluggish charge transport kinetics, confined light absorption scope, limited active species, and rapid charge recombination rate. Herein, we conceptually demonstrate the elaborate design of all transition metal chalcogenides (TMCs)-comprising heterostructures via a facile, controllable, and precise cascade cation exchange strategy. This progressive route strategically extends the light absorption of TMCs, engenders elegant heterostructured interface, and furnishes favorable energy level alignment. The resultant TMCs heterostructures demonstrate markedly enhanced and multifarious photoactivities, owing predominantly to the robust interfacial electronic coupling and applicable energy level configuration among the building blocks, synergistically resulting in the reinforced charge transfer impetus and considerably prolonged charge lifespan. Our work would provide an emerging avenue to fine tuning of vectorial charge motion via such a judicious interface modulation strategy for solar-to-chemical energy conversion.

Anchoring cobalt single atoms on 2D covalent triazine framework with charge nanospatial separation for enhanced photocatalytic pollution degradation

Covalent triazine frameworks (CTFs) show great potential in photocatalytic fields, while their practical efficiency is still limited due to rapid charge recombination. Here we report a nanospatial separation strategy for photoinduced electron-hole pairs of CTF-1 nanosheets via single-atom Co using facile pyrolysis and phosphorization to form stable Co–N3 (≈1.60 Å) architecture. HAADF-STEM image demonstrates Co atoms are uniformly dispersed onto ultrathin CTF-1. The local structure surrounding and chemical valent state of Co are systematically investigated by Fourier-transformed EXAFS and K-edge XANES, respectively. Co single atoms as oxidation centers can capture holes transferred from CTF-1, thus resulting in narrow bandgap and improved photo-exciton dissociation in the two-dimensional (2D) direction. The obtained Co/CTF-1 exhibits excellent efficiency of 99.9% for pollutant photodegradation, far outperforming that of pristine CTF-1 (68.8%). Nanospatial separation endows Co/CTF-1 with various micropollution removal capabilities, outstanding cyclic stability, and a widely effective pH range (1.0–11.0) under visible light. Furthermore, active oxidating radicals of h+ and •O2− are dominant in photocatalytic degradation for various organic contaminants. This study motivates the atomic design and fabrication of 2D photocatalysts with excellent charge nanospatial separation.

Carbon dots with different energy levels regulate the activity of metal-free catalyst for hydrogen peroxide photoproduction

Artificial photoproduction of hydrogen peroxide (H2O2) from H2O and O2 by metal-free catalysts (e.g., graphitic carbon nitride) is regarded as an ultra-clean approach. Metal-free catalysts are often hindered by unpropitious rapid charge recombination and unfavorable selectivity. Herein, three carbon dots (CDs1 to CDs3) decorated modified-carbon nitride (CDs1-NCN, CDs2-NCN and CDs3-NCN) were designed and fabricated, which show diverse activity of H2O2 photoproduction. Among them, CDs1-NCN, as a two-channel photocatalyst, achieves H2O2 production with high efficiency (1938 μmol h−1 g−1). This process is at normal pressure and without sacrificial agent under visible region (λ≥420nm), which is 27.5- times higher than that of pristine C3N4. The apparent quantum efficiency can be calculated to 7.03 % (λ=365nm). In this system, CDs with different energy levels dominate the activity of metal-free catalyst for hydrogen peroxide photoproduction. Combining with photoelectrochemical test and transient photovoltage analysis, the active site and the catalytic mechanism of these composite catalysts are also clarified. Our work provides a clearly insight for understanding of the regulation of interfacial electron transport in metal-free photocatalysts.

Molecular design strategy for realizing vectorial electron transfer in photoelectrodes

<h2>Summary</h2> Vectorial electron transfer is essential for developing ideal artificial photosystems. Conventional photosensitizers with only strong electronic coupling, as used in photovoltaics, cannot achieve vectorial electron transfer because of their rapid charge recombination. Herein, we present a design strategy for integrating strong (∼600 cm⁻¹) and relatively weak (310 cm⁻¹) electronic coupling in a single molecule to realize vectorial electron transfer in dye-sensitized solar cells. Four sensitizers with donor-acceptor-π-spacer and anchoring group configurations are developed, and the electronic coupling in these sensitizers is controlled by the π-spacers of varying steric hindrances. Transient-absorption spectroscopies reveal the occurrence of vectorial electron transfer in the designed sensitizer by suppressing charge recombination via weakened electronic coupling between the acceptor and π-spacer and the efficient charge injection via strong electronic coupling between the donor and acceptor. The optimization of electronic coupling in the sensitizers improves the photovoltaic performances, achieving a power-conversion efficiency of 10.8%.

Design of Ag3VO4/ZnO nanocrystals as visible-light-active photocatalyst for efficient and rapid oxidation of ciprofloxacin antibiotic waste

BackgroundOxidative mineralization of antibiotic waste by visible light active semiconductor photocatalysts become an important issue to prevent the possible crisis of antimicrobial resistance to these materials. On the other hand, the engineered design of sustainable and efficient photocatalyst is still under development stage due to some obstacles like large bandgap energy (Eg) and the rapid charge recombination MethodsIn this work, a surfactant-assisted sol-gel process is used to synthesize mesostructured ZnO nanocrystals which are subsequently loaded with minor amounts (1.0–4.0 wt.%) of nanocrystalline Ag3VO4 by coprecipitation to form heterostructured Ag3VO4/ZnO photocatalyst. Significant findingsProduced nanostructures revealed the uniform distribution of ∼5.9 nm of monoclinic Ag3VO4 decorating 58.6 nm wurtzite ZnO nanocrystals as confirmed by XRD, TEM, and XPS characterizations. In addition, the samples displayed a mesoporous texture with 123–150 m2 g‒1 of surface area. The incorporation of Ag3VO4 to ZnO enhanced visible-light harvesting and reduced Eg from 3.34 to ∼2.4 eV. The designed photocatalysts showed a rapid photooxidation of ciprofloxacin (CPF) as an emerging antibiotic pollutant in the water. The 3.0% Ag3VO4/ZnO revealed complete mineralization of 10-ppm CPF within 45 min of visible-light irradiation at workable reusability. This magnificent performance is referred to as the homogenous distribution of Ag3VO4 on the ZnO surface that allows efficient separation and mobility of photoinduced charges and subsequent oxidation of CPF in a short time.

Rational design of ZnO-zeolite imidazole hybrid nanoparticles with reduced charge recombination for enhanced photocatalysis

Semiconducting zinc oxide nanoparticles (ZnO NPs) hold great potential as photocatalysts in wastewater treatment because of their favorable bandgap and cost-effectiveness. Unfortunately, ZnO NPs usually show rapid charge recombination that limits their photocatalytic efficacy significantly. Herein, we report a facile way of modifying ZnO NPs with zeolite imidazole framework-8 (ZIF8). A synergy between the two components may tackle the drawback of fast charge recombination for pristine ZnO NPs. Improved performance of photocatalytic degradation of methylene blue (MB) is confirmed by comparing with pristine ZnO and ZIF8 as the catalysts. The ZIF8 in the composite serves as a trap for photogenerated electrons, thus reducing the rate of charge recombination to enhance the photocatalysis rate. In addition, the hybridization process suppresses the aggregation of ZnO NPs, providing a large surface area and a greater number of active sites. Moreover, a small shift in the absorption band of ZnO@ZIF8 (10) NPs towards higher wavelength, also witnessed a little contribution towards enhanced photocatalytic properties. Mechanistic studies of the photocatalytic process of MB using ZnO@ZIF8 NPs catalyst reveal that hydroxyl radicals are the major reactive oxygen species. The facile hybridization of ZnO with ZIF8 provides a strategy for developing new photocatalysts with wide application potential.

Coupling morphology control and surface I grafting for boosting the photocatalytic activity of Bi2O2[BO2(OH)] nanosheets

Photocatalytic performance of semiconductors is currently limited by low solar light utilization, rapid charge recombination and limited reactive sites. Reducing the thickness of layered photocatalysts can shorten the charge transport distance to inhibit their recombination and provide more reactive sites. Surface ionic grafting can broaden the light absorption range and promote the separation efficiency of carriers. In this work, the surface iodine ion modified Bi2O2[BO2(OH)] nanosheets are synthesized by combining the surfactant-assisted hydrothermal method and room-temperature KI solution treatment route. These nanosheets show increased photoabsorption in visible region, enlarged specific surface area and promoted charge separation. Compared with the pristine Bi2O2[BO2(OH)], the surface I- modified Bi2O2[BO2(OH)] nanosheets exhibit substantially strengthened photocatalytic performance for degradation of BPA, which increases beyond 25 times. The total organic carbon content (TOC) test reveals that the mineralization process of BPA. Electron spin resonance (ESR) measurements disclose the radicals that play dominant role in the photocatalytic process and confirm their increased yield over I- modified Bi2O2[BO2(OH)] nanosheets. In addition, BiOB-S-I2 also shows universality for degradation of a variety of high-concentration pollutants, including rhodamine B, methyl orange, methylene blue, phenol, 2,4-dichlorophenol and tetracycline hydrochloride. This study may provide a combined strategy for exploring high-performance photocatalysts via microstructure control and surface ionic decoration.

Enhanced charge separation in La2NiO4 nanoplates by coupled piezocatalysis and photocatalysis for efficient H2 evolution.

Photocatalytic hydrogen evolution is one promising method for solar energy conversion, but the rapid charge recombination limits its efficiency. To this end, in this work, grain size, and hence the charge carrier migration path, is reduced by lowering the synthesis temperature of two-dimensional visible light-responsive La2NiO4 perovskite. Interestingly, the hydrogen yield for the piezoelectric response of La2NiO4 under only 40 kHz ultrasonic vibration is as high as 680 μmol h-1 g-1, which is 80 times that under only 600 mW cm-2 visible light irradiation. More surprisingly, the hydrogen production rate under both light illumination and ultrasonic vibration is 129 times higher than under visible light irradiation alone. Clearly, a synergistic effect exists between piezocatalysis and photocatalysis. The hydrogen production activity of the samples with water splitting can reach 1097 μmol h-1 g-1 without any sacrificial reagent or co-catalyst, when the light intensity reaches about 1000 mW cm-2, which is a much higher hydrogen evolution rate by piezo-photocatalysis than is achieved by either piezocatalysis or photocatalysis individually. Further analysis indicates that the internal electric field generated by deformation of the La2NiO4 edge under piezoelectric action facilitates the directional separation and migration of photogenerated charges, which in turn significantly enhances the efficiency of use of photogenerated charges for hydrogen production. The investigation here provides a novel approach to design a new reaction system for hydrogen production by coupling multiple external physical fields.

Biotemplated g-C3N4/Au Periodic Hierarchical Structures for the Enhancement of Photocatalytic CO2 Reduction with Localized Surface Plasmon Resonance.

Graphitic carbon nitride (g-C3N4) is a promising photocatalyst for CO2 reduction to alleviate the greenhouse effect. However, the low light absorption, small specific surface area, and rapid charge recombination limit the photocatalytic efficiency of g-C3N4. Herein, we demonstrate a bioinspired nanoarchitecturing strategy to significantly improve the light harvesting and charge separation of the g-C3N4/Au composite, as proven by the remarkable photocatalytic CO2 reduction. Specifically, a biotemplating approach is employed to transfer the sophisticated hierarchical structures and the related light-harvesting functionality of Troides helena butterfly wings to the g-C3N4/Au composite. The resulting g-C3N4/Au composite shows high photocatalytic efficiency under UV-visible excitation with triethanolamine as the sacrificial agent. The yields of CO and CH4 are 331.57 and 39.71 μmol/g/h, respectively, which are ∼36 times and ∼88 times that of pure g-C3N4 under the same conditions. Detailed experiments and the finite-difference time-domain method suggest that the superb photocatalytic activity should be ascribed to the unique periodic hierarchical structure which assists the light absorption and the localized surface plasmon resonance for promoted charge separation in addition to the more effective CO2 diffusion and larger specific surface area. Our work provides a new path for the design and optimization of photocatalysts based on biological structures that are usually unattainable artificially.

Rational Design and Synthesis of OEP and TPP Centered Phosphorus(V) Porphyrin-Naphthalene Conjugates: Triplet Formation via Rapid Charge Recombination.

Six new "axial-bonding" type "phosphorus(V) porphyrin-naphthalene" conjugates have been prepared consisting of octaethylporphyrinatophosphorus(V) (POEP+)/tetraphenylporphyrinatophosphorus(V) (PTPP+) and naphthalene (NP). The distance between the porphyrin and NP was systematically varied using polyether bridges. The unique structural topology of the octaethylporphyrinatophosphorus(V) (POEP+) and tetraphenylporphyrinatophosphorus(V) (PTPP+) enabled construction of mono- and disubstituted phosphorus(V) porphyrin-naphthalene conjugates, respectively. The steady-state and transient spectral properties were investigated as a function of redox properties, distance, and molecular topology. Strong electronic interactions between the phosphorus(V) porphyrin and NP in directly bound conjugates were observed. The established energy diagrams predicted reductive electron transfer involving singlet excited phosphorus(V) porphyrin and NP to generate high-energy (∼1.83-2.11 eV) charge-separated states (POEP/PTPP)•-(NP)•+. Femtosecond transient absorption spectral studies revealed rapid deactivation of singlet excited phosphorus(V) porphyrin due to charge separation wherein the estimated forward rate constants were in the range of 109-1010 s-1 and were dependent on the distance between the NP and porphyrins units, as well as the redox potentials of the type of the phosphorus(V) porphyrin. Additionally, due to high exothermicity and low-lying triplet states, the charge recombination process was found to be rapid, leading to populating the triplet states of phosphorus(V) porphyrins.

One step-polymerization for constructing 1D/2D oxygen doped g-C3N4 isotype heterojunctions with highly improved visible-light-driven photocatalytic activity

Constructing an isotype 1D/2D O-doped g-C3N4 heterojunction to boost the efficiency of g-C3N4 for the decomposition of organic pollutants under visible light irradiation is a practical approach. It is possible to use such materials to overcomes g-C3N4’s inherent disadvantage of rapid charge recombination. In this work, a straightforward, one-step self-polymerization technique for fabricating 1D/2D O-doped g-C3N4 isotype heterojunctions comprise of O-doped g-C3N4 nanotubes and nanosheets is presented here. A plausible formation mechanism supported by XRD and FT-IR analyses is proposed and investigated. The obtained results show that the fabricated materials exhibit a high surface area (114.4 m2 g−1) while the PL technique confirmed the rapid charge separation. Compared with the as-fabricated 2D g-C3N4 nanosheets, 1D/2D O-doped g-C3N4 isotype heterojunctions possess superior photocatalytic activity for RhB degradation under visible light illumination. The degradation pathway was investigated using LC-MS analysis. The improved photocatalytic degradation ability of 1D/2D O-doped g-C3N4 isotype heterojunctions is attributed to the enhanced absorption capability, high surface area, and separation efficiency of photogenerated charge carriers.

Novel donor-acceptor-acceptor ternary conjugated microporous polymers with boosting forward charge separation and suppressing backward charge recombination for photocatalytic reduction of uranium (VI)

The photoreduction of soluble U(VI) to insoluble U(IV) with conjugated microporous polymers (CMPs) is a promising channel to remove uranium from radioactive wastewater efficiently. However, the rapid backward charge recombination and unsatisfactory forward charge transfer lead to undesirable photocatalytic activity of CMPs. Herein, for the first time, a series of D-A1-A2 terpolymers is developed with statistical copolymerization through adjusting the monomer feed molar ratio (FMR) for photoreduction of uranium. Compared with D-A binary copolymer, such D−A1−A2 terpolymers can inhibit charge recombination and simultaneously facilitate charge separation due to its larger dipole moment and giant built-in electric field. Therefore, the PTrSO-2 which the FMR is 0.75: 1.0: 0.75 achieves 99.5% photocatalytic U(VI) reduction efficiency within 120 min visible-light irradiation, outshining most reported photocatalysts for such applications. This work cultivates an emerging stratagem and unconventional thinking for the development of CMPs photocatalysts used in the effective treatment of radioactive wastewater.

Intramolecular Charge‐Transfer Dynamics in Benzodifuran‐Based Triads

AbstractA facile and efficient approach for the synthesis of new conjugated donor‐π‐acceptor (D‐π‐A) chromophores has been developed, in which benzodifuran (BDF) and/or triphenyl amine (TPA) units are the donor moieties, linked by ethylenic bridges to electron‐deficient anthraquinone (AQ) and 11,11,12,12‐tetracyano‐9,10‐anthraquinodimethane (TCAQ) as the acceptor moieties. The resultant triads either with a symmetric A–D–A or an asymmetric D′–D–A structure show intense absorption bands in the visible spectral region due to efficient intramolecular charge transfer (ICT) from the HOMO localized on the BDF core to the LUMO localized on the AQ or the TCAQ unit. Electronic interactions between these redox‐active components were studied by a combination of cyclic voltammetry, spectroelectrochemistry, UV‐visible and ultrafast transient absorption spectroscopy. Analysis of the femtosecond excited‐state dynamics reveal that all triads undergo a rapid charge recombination process which occurs within a few picoseconds, indicating that ethylenic linkers can facilitate electron delocalization among BDF and AQ/TCAQ units and thus impart effective electronic interactions between them.

Simultaneously Tuning Band Structure and Oxygen Reduction Pathway toward High‐Efficient Photocatalytic Hydrogen Peroxide Production Using Cyano‐Rich Graphitic Carbon Nitride

AbstractThe demands for green production of hydrogen peroxide have triggered extensive studies in the photocatalytic synthesis, but most photocatalysts suffer from rapid charge recombination and poor 2e− oxygen reduction reaction (ORR) selectivity. Here, a novel composite photocatalyst of cyano‐rich graphitic carbon nitride g‐C3N4 is fabricated in a facile manner by sodium chloride‐assisted calcination on dicyandiamide. The obtained photocatalysts exhibit superior activity (7.01 mm h−1 under λ ≥ 420 nm, 16.05 mm h−1 under simulated sun conditions) for H2O2 production and 93% selectivity for 2e− ORR, much higher than that of the state‐of‐the‐art photocatalyst. The porous g‐C3N4 with Na dopants and cyano groups simultaneously optimize two limiting steps of the photocatalytic 2e− ORR: photoactivity, and selectivity. The cyano groups can adjust the band structure of g‐C3N4 to achieve high activity. They also serve as oxygen adsorption sites, in which local charge polarization facilitates O2 adsorption and protonation. With the aid of Na+, the O2 is reduced to produce more superoxide radicals as the intermediate products for H2O2 synthesis. This work provides a facile approach to simultaneously tune photocatalytic activity and 2e− ORR selectivity for boosting H2O2 production, and then paves the way for the practical application of g‐C3N4 in environmental remediation and energy supply.

Hollow cubic Cu2-xS/Fe-POMs/AgVO3 dual Z-scheme heterojunctions with wide-spectrum response and enhanced photothermal and photocatalytic-fenton performance

The assembly photocatalyst with rational design of nanostructure can effectually inhibit the rapid charge recombination and improve the photocatalytic performance. Herein, a hollow cubic Cu2-xS/Fe-polyoxometalate/AgVO3 (Cu2-xS/Fe-POMs/AgVO3) dual Z-scheme heterojunction superstructure is constructed on the surface of a hollow cubic Cu2-xS with a clear structure by continuous growth deposition. The hollow cube structure can promote the utilization of light through the refraction and reflection of light in the cavity. Fe-POMs act as the linker between Cu2-xS and AgVO3, providing adequate active sites. In addition, due to the surface plasmon resonance effect of Cu2-xS, Cu2-xS/Fe-POMs/AgVO3 has an obvious photothermal effect, which extends the photoresponse to near-infrared region. The hollow cubic Cu2-xS/Fe-POMs/AgVO3 photocatalyst has excellent photocatalytic-Fenton degradation rate of 98.6 % for bisphenol A within 150 min due to the formation of dual Z-scheme heterostructures benefiting spatial charge separation. This work provides new insights for fabricating superstructure photocatalyst with high-performance and broad-spectrum response.

Temperature-responsive polymer-tethered Zr-porphyrin MOFs encapsulated carbon dot nanohybrids with boosted visible-light photodegradation for organic contaminants in water

Zirconium-based porphyrin metal–organic frameworks (MOFs) have attracted extensive attention in the photocatalysis because of their considerable specific surface area, powerful visible light efficiency and semiconductor properties. However, the rapid charge recombination and self-aggregation limit their applications. Here, porphyrin-based Zr-MOF (PCN-222) nanohybrids (CDs@PCN-222@PNIPAM) as an efficient hydrophilic photocatalyst were fabricated by encapsulating various carbon dots (CDs) into PCN-222 nanopores with surface wettability modification by catechol-terminated thermo-responsive PNIPAM having various chain lengths. Due to the electron collecting effect of the nitrogen-doped CDs (N-CDs) and their synergistic effect with PCN-222, the photocatalytic performance of the prepared nano-hybrid photocatalyst were significantly improved. Furthermore, the introduction of hydrophilic polymer with moderate molecular weight effectively enhanced the transfer efficiency of photo-generated charges and the surface wettability of photocatalyst, and improved the water dispersibility of catalyst so that effectively promotes the enrichment and catalytic conversion of water-soluble target pollutants around the active site of the photocatalyst. The removal efficiency of RhB and tetracycline (TC) under visible light irradiation reached almost 100 % and 90.93 % in just 20 min, respectively. In addition, polymer-functionalized Zr-MOF-based nanohybrids revealed an interesting temperature-response switching behavior for the photocatalysis. The study on the catalytic mechanism and degradation pathways of TC showed that the h+ plays a major role in the degradation process, and other reactive species are also involved in the further mineralization of pollutants. This work provides a new insight for the functional modification of MOFs and the design of high efficiency photocatalyst.

Development of Visible-Light-Driven Rh–TiO2–CeO2 Hybrid Photocatalysts for Hydrogen Production

Visible-light-driven hydrogen production through photocatalysis has attracted enormous interest owing to its great potential to address energy and environmental issues. However, photocatalysis possesses several limitations to overcome for practical applications, such as low light absorption efficiency, rapid charge recombination, and poor stability of photocatalysts. Here, the preparation of efficient noble metal–semiconductor hybrid photocatalysts for photocatalytic hydrogen production is presented. The prepared ternary Rh–TiO2–CeO2 hybrid photocatalysts exhibited excellent photocatalytic performance toward the hydrogen production reaction compared with their counterparts, ascribed to the synergistic combination of Rh, TiO2, and CeO2.