Enhancement Of Photocatalytic Performance Research Articles

Enhancing photocatalytic performance of covalent organic frameworks via ionic polarization

Covalent organic frameworks have emerged as a thriving family in the realm of photocatalysis recently, yet with concerns about their high exciton dissociation energy and sluggish charge transfer. Herein, a strategy to enhance the built-in electric field of series β-keto-enamine-based covalent organic frameworks by ionic polarization method is proposed. The ionic polarization is achieved through a distinctive post-synthetic quaternization reaction which can endow the covalent organic frameworks with separated charge centers comprising cationic skeleton and iodide counter-anions. The stronger built-in electric field generated between their cationic framework and iodide anions promotes charge transfer and exciton dissociation efficiency. Moreover, the introduced iodide anions not only serve as reaction centers with lowered H* formation energy barrier, but also act as electron extractant suppressing the recombination of electron-hole pairs. Therefore, the photocatalytic performance of the covalent organic frameworks shows notable improvement, among which the CH3I-TpPa-1 can deliver an high H2 production rate up to 9.21 mmol g−1 h−1 without any co-catalysts, representing a 42-fold increase compared to TpPa-1, being comparable to or possibly exceeding the current covalent organic framework photocatalysts with the addition of Pt co-catalysts.

Rational design of Z-scheme configured polymeric carbon nitride-decorated ZnWO4 nanofibers for enhanced visible-light-driven photodegradation of antibiotics

In this study, a Z-scheme heterostructure was meticulously engineered between zinc tungstate (ZnWO4) nanofibers and polymeric carbon nitride (PCN) nanosheets to augment the photocatalytic degradation of tetracycline (TC) under visible light irradiation. A cohesively integrated PCN/ZnWO4 photocatalyst structure was synthesized through an in-situ gas-solid reaction. The quantity and spatial distribution of PCN nanosheets were modulated by fine-tuning the gas precursor and reaction parameters. Relative to pristine ZnWO4 nanofibers and PCN photocatalysts, the distinct three-dimensional PCN/ZnWO4 heterostructure manifests a notable enhancement in photocatalytic performance, attributed to its plethora of active sites and a Z-scheme configuration that bolsters charge separation efficiency, achieving a tetracycline degradation rate of 95.4% upon exposure to simulated sunlight for 160 minutes. The employment of gas-solid reaction as a design paradigm pioneers a fresh paradigm in the strategic assembly of Z-scheme heterostructured photocatalysts, thereby illuminating a promising pathway for advancements in environmental remediation technologies.

General Synthesis of Single-Crystalline Ta2O5 Nanorods Towards Enhanced Photocatalytic H2 Production Activity.

As a potential candidate for photocatalytic H2 production from water splitting, Ta2O5 catalyst presents suitable conduction and valence band positions, but suffers from poor charge transfer ability, which seriously limits its photocatalytic performance enhancement. Here, a facile and eco-friendly hydrothermal method was developed for the fabrication of one-dimensional (1D) Ta2O5 nanorods using the freshly precipitated tantalic acids as the precursors. An oriented attachment mechanism was proposed for the growth of Ta2O5 nanorods. Moreover, the present synthetic approach was further extended to direct synthesis of nine kinds of alkaline tantalates and alkaline-earth tantalates nanostructures, suggesting its general applicability. A significant increase in activity in photocatalytic H2 production was revealed on 1D Ta2O5 nanorods. The improved photocatalytic H2 production activity of Ta2O5 nanorods was mainly attributed to its 1D nanorods structure with high crystallization and large specific surface areas as well as excellent charge transfer efficiency.

Construction of Ag-modified ZnO/g-C3N4 heterostructure for enhanced photocatalysis performance.

ZnO/g-C3N4 heterojunction modified with Ag nanoparticles (ZnO/CN/Ag) was synthesized by depositing ZnO nanorods/Ag nanoparticles onto g-C3N4 nanosheets. Under xenon lamp irradiation, 99% of Rhodamine B (RhB) was degraded by ZnO/CN/Ag-5% composite within 30min, which was much higher than the degradation efficiency of ZnO and ZnO/CN. The synergistic effect of g-C3N4 and ZnO, along with the localized surface plasmon resonance effect of Ag NPs, contributes to the improvement of photocatalytic performance. Ag nanoparticle provides another charge transfer path from g-C3N4 to ZnO, which speeds up the separation of electron-hole pairs. Meanwhile, the catalyst had good stability and recyclability. Finite-difference time-domain method and the density functional theory were used to obtain the charge transfer process. The photodegradation process has been studied in depth.

Synthesis of a novel flower-like Bi4Ti3O12/AgI Z-type heterojunction for efficient photocatalytic removal of tetracycline antibiotic and RhB

Novel Flowerlike Bi4Ti3O12/AgI (BTO/AgI) Z-type heterojunctions were fabricated via a straightforward in-situ precipitation method. Notably, BTO/AgI exhibited significantly improved photodegradation efficiency for tetracycline (TC) and Rhodamine B (RhB). The rate constants for RhB and TC photodegradation were approximately 20.8 and 2.9 times higher than those of BTO alone, respectively. Furthermore, the photocatalytic efficiency of the BTO/AgI heterojunction is 1.4 times higher than that of the mixture of the two individual photocatalysts, indicating a robust interaction between BTO and AgI. This enhancement in photocatalytic performance was mainly attributed to the effective separation of photogenerated carriers facilitated by the Z-scheme heterojunction, which can be demonstrated by the highest photocurrent density (∼0.307 μA·cm−2) of BTO/AgI, surpassing BTO (∼0.073 μA·cm−2) and AgI (∼0.161 μA·cm−2) by approximately 4.12 and 1.91 times, respectively. Furthermore, three plausible photodegradation pathways of tetracycline were proposed. This study introduces a novel approach for designing and synthesizing high-efficiency Z-scheme photocatalysts for the degradation of TC and RhB in wastewater.

Anchoring TiO2 and CuO nanoparticles on SnO2 nanotube arrays to construct ternary heterostructure for visible-light-driven photocatalytic degradation of green malachite dye

Designing and constructing heterostructure photocatalysts is necessary to facilitate the long-term separation of photogenerated charge carriers and enhance photocatalytic efficiency. Herein, a ternary nanocomposite photocatalyst based on SnO2, TiO2 and CuO semiconductors was successfully synthesized and employed as a highly effective photocatalyst for the malachite green (MG) dye degradation under visible light irradiation. According to the results, the ternary SnO2/TiO2/CuO nanocomposite demonstrated impressive photocatalytic activity (98.4 %) compared to pristine SnO2 nanotubes (40.3 %), binary SnO2/TiO2 (76 %) and SnO2/CuO nanocomposites (88 %), when exposed to 90 min of visible illumination. The photoreaction rate constant of SnO2/TiO2/CuO nanocomposite (0.0482 min−1) was found to be ∼8.5 times faster than SnO2 nanotubes (0.0057 min−1) against MG dye. This enhancement in photocatalytic performance can be attributed to the introduction of TiO2 and CuO which effectively suppress the recombination of photogenerated electron-hole pairs, accelerate the transfer of charge carriers, increase the active sites, and improve the optical absorption properties. Scavengers were used to elucidate the photocatalytic mechanism, exhibiting the pivotal role of •O2− and h+ in the photodegradation process. Besides, recyclability tests showed acceptable results after four cycles, confirming the stability and durability of the SnO2/TiO2/CuO nanocomposite against RhB dye degradation.

Enhancing photocatalytic performance of SnO2/ZnS nanocomposites synthesized via dual-step precipitation and ultrasonicated hydrothermal route

SnO2/ZnS nanocomposites were successfully synthesized using a modified hydrothermal route. The synthesis involved separate co-precipitation of SnO2 and ZnS, followed by ultrasonic stirring and hydrothermal treatment. The resulting nanocomposites exhibited controlled size and composition. By adjusting synthesis parameters such as the molar ratio of Sn to Zn, reaction temperature, and reaction time, the morphology and properties of the nanocomposites could be finely tuned. The synthesized SnO2/ZnS nanocomposites demonstrated remarkable improvements in photocatalytic performance compared to pure SnO2 or ZnS nanoparticles. This enhancement was attributed to the nanocomposites' enhanced charge separation, increased surface area, and improved light absorption capabilities. As a result, the SnO2/ZnS nanocomposites hold great promise for a wide range of applications, including environmental remediation, water splitting, and solar energy conversion.

Unravelling charge carrier dynamics for enhancement of photocatalytic performance in Pd/MoS2 nanocomposites for water remediation of real-world pollutants

In this study, Pd/MoS2 nanocomposites were successfully synthesized incorporating Pd nanoparticles into three-dimensional (3D) flower-like MoS2 nanostructures. The controlled introduction of Pd was aimed to optimize the photocatalytic performance of the resulting nanocomposites, which exhibited exceptional efficiency in degrading various organic pollutants and antibiotic tetracycline (TC) under simulated solar light irradiation. The nanocomposites with an optimized Pd concentration of 2.5 % demonstrated outstanding photocatalytic efficiency, achieving the degradation of Rhodamine B (RhB), Methylene blue (MB), TC by 98 %, 98 %, and 96 %, respectively, with specific interval of 40, 30 and 60 min. The reaction rate constant of the Pd/MoS2 nanocomposites was measured to be 0.7798 min−1 using pseudo first-order rate kinetics. The value is about 19 times higher than that of pure MoS2 (0.00414 min−1) for degradation of RhB. The improved photocatalytic performance of these nanocomposites can be attributed to several factors. Firstly, the incorporation of Pd nanoparticles substantially enhanced their light absorption capabilities, leading to an overall increase in photocatalytic efficiency. Moreover, the presence of Pd contributed to a large surface area, further enhancing the nanocomposite's photocatalytic potential. Importantly, the formation of a built-in electric field at Pd/MoS2 interface facilitated the efficient separation of the electron-hole pairs, extending the life time of these photoinduced charge carriers. This study offers valuable insights into development of MoS2-based photocatalyst, which hold significant promise for addressing water pollution challenges and making substantial contributions to the field of water purification and environmental remediation.

Enhancing photocatalytic performance of rose-shaped Co/Ni bimetallic organic framework for reducing CO2 to CO under visible light

Co-MOF-74, composed of Co salt as the metal source and 2,5-dihydroxyterephthalic acid as the organic ligand, is widely used as a catalyst for the photocatalytic reduction of CO2 due to its open metal sites, high porosity, large specific surface area, and high CO2 adsorption capacity. However, its effectiveness in CO2 conversion is limited by weak electron transfer capabilities and a high rate of electron/hole pair recombination. To address these limitations, a bimetallic strategy was employed to significantly improve the catalytic performance of Co-MOF-74 for photocatalytic CO2 reduction. Stable bimetallic Co/Ni-MOF-74-x (x = 1, 2, 3) with controllable morphology and metal ratios were synthesized by adjusting the molar ratios of Co2+ and Ni2+ and combining them with 2,5-dihydroxyterephthalic acid. The introduction of Ni2+ led to a significant increase in the specific surface area, from 204.999 m2/g (Co/Ni-MOF-74) to 790.873 m2/g (Co/Ni-MOF-74-1). In addition, the band gap of bimetallic Co/Ni-MOF-74-1 was narrowed to 1.4 eV, which enhanced charge transfer. As a result, photocatalytic experiments demonstrated that the CO2 conversion efficiency of bimetallic Co/Ni-MOF-74-1 was significantly improved, reaching 4.539 mmol/g/h, compared to that of the monometallic Co-MOF-74. Finally, a synergistic photocatalytic mechanism involving ligand activation was proposed to explain the reaction process of the bimetallic Co/Ni-MOF-74 catalyst. Meanwhile, this study highlights that the bimetallic strategy is an effective approach to optimizing the performance of MOF catalysts for the photocatalytic reduction of CO2.

0D/2D S-scheme heterojunction of cadmium selenide and covalent triazine frameworks with enhanced photocatalytic activity for hydrogen evolution, carbon dioxide reduction and terpene dehydrogenation

The step-scheme (S-scheme) heterojunction shows the merits of controlling the directional transfer of photogenerated charge carriers and realizing a strong redox potential for photocatalytic hydrogen evolution and carbon dioxide reduction. In this paper, a zero/two-dimensional (0D/2D) S-scheme heterojunction composed of cadmium selenide quantum dots and covalent triazine frameworks (CdSe/CTF) is designed and fabricated by an electrostatic self-assembly approach. Compared with pristine CTF and CdSe quantum dots, the photocatalytic activities of CdSe/CTF composites for hydrogen evolution, carbon dioxide reduction and terpene oxidation are significantly enhanced. The hydrogen evolution rate of CdSe/CTF hybrid photocatalyst immobilized with platinum nanoparticles as cocatalyst reached 19.0 mmol g−1 h−1 under visible-light irradiation, and the apparent quantum yield is 9.8 % at 420 nm. The CdSe/CTF hybrid also exhibited more superior photocatalytic activity in carbon dioxide reduction with a carbon monoxide evolution rate of 1.48 mmol g−1 h−1, and presented higher photocatalytic reactivity in the selective oxidation of α-terpinene to p-cymene. The remarkable enhancement of photocatalytic performance for CdSe/CTF composite is mainly attributed to the facilitated separation and transfer of photoexcited charge carriers of 0D/2D S-scheme heterojunction. This work provides an in-depth insight of utilizing semiconducting polymers as a suitable platform to sustainably transform inexhaustive solar energy to storable chemical energy.

Optimizing catalytic performance of Ag2O/Na0.5Bi0.5TiO3 heterojunction by the piezo-phototronic coupling effect

The constructing of heterojunction piezo-photocatalysts has been regarded as a promising strategy in environmental remediation. Herein, a novel Ag2O/Na0.5Bi0.5TiO3 (Ag2O/NBT) p-n heterojunction is designed by using a facile method, inducing the remarkable enhancement of photocatalytic performance by piezoelectric effect under ultrasonic vibration. The Ag2O/NBT heterojunction can degrade 99 % Rhodamine B (RhB) within 30 min when exposed to light irradiation and ultrasonic vibration simultaneously, with a high reaction rate constant of 0.140 min−1, which is 4.5 times and 17.5 times that of individual photocatalysis (0.031 min−1) and piezocatalysis (0.008 min−1), respectively. Moreover, the Ag2O/NBT heterojunction exhibits excellent stability and reusability after five cycles. The improved piezo-photocatalytic performance can be attributed to the formation of p-n heterojunction and the generation of built-in electric field, which makes a high separation of photogenerated carriers. Finally, a possible piezo-photocatalytic mechanism for removal RhB was proposed based on the radical trapping experiment. It is expected that the results can provide valuable information for the further investigations of Ag2O/NBT heterojunction as a potential piezo-photocatalyst in the environmental remediation.

Synergistic photocatalytic and antibacterial efficacies of Ag/rGO and Ag/Ag2O/rGO nanocomposites: The impact of oxide formation and ternary heterojunction

This study explores the efficient solvothermal integration of Ag/rGO and Ag/Ag2O/rGO nanocomposites using various solvents and employs thorough characterization procedures. The primary focus is on understanding the nuanced effects resulting from the combination of Ag nanoparticles with rGO nanosheets, particularly in the context of Ag2O formation. For a quantitative assessment of their photocatalytic and antibacterial properties, graphene oxide and silver nitrate (AgNO3) were introduced to create Ag/rGO and Ag/Ag2O/rGO nanocomposites. The results demonstrate a significant enhancement in photocatalytic performance for the Ag/Ag2O/rGO nanocomposite, achieving a rapid degradation of 99.99 % of methylene blue dye within 30 minutes under simulated solar light irradiation. This heightened efficiency is attributed to improved separation and transfer efficiency, as well as the substantial generation of photoinduced carriers due to the incorporation of visibly active Ag2O nanoparticles. Moreover, the Ag/Ag2O/rGO nanocomposite exhibits an enhanced antibacterial activity, reflected in Minimum Inhibitory Concentration (MIC) values of 50 μg/ml for Bacillus cereus and 300 μg/ml for Escherichia coli. The nanocomposite's higher antimicrobial activity against Gram-positive bacteria, particularly Bacillus cereus, is underscored, revealing its potential as an effective antibacterial agent. The formation of a ternary heterojunction in the Ag/Ag2O/rGO nanocomposite results in a notable increase in the production of free radicals, enhancing charge carrier migration and separation efficiency. This quantitative evidence emphasizes the versatile nature of the nanocomposite, highlighting its potential across diverse fields through augmented antibacterial and photocatalytic properties.

In situ constructing 2D/2D layered BiOBr/Bi2O2CO3 heterostructure for efficient photocatalytic reduction CO2 to CO

Photocatalytic reduction of CO2 to valuable energy materials is necessary for sustainable development. It is a considerable challenge to prepare photocatalysts for CO2 photoreduction with excellent separation capability of carriers by simple way. Herein, the BiOBr/Bi2O2CO3 type-II heterostructure was constructed by in situ conversion at room temperature. Combining the advantages of the 2D/2D layered structure can form a close contact interface and the type-II heterostructure can facilitate the transport of photogenerated charges, the BiOBr/Bi2O2CO3 composite showed significant enhancement in photocatalytic CO2 reduction performance. The most obvious performance enhancement was observed for 2.0-BiOBr/Bi2O2CO3, where CO yield could reach 29.55 μmol·g−1 for 3 h under light irradiation, it is 11 and 4 times higher than Bi2O2CO3 and BiOBr, respectively. And the sample exhibits excellent cycling stability in photocatalytic tests. In situ Fourier Transform Infrared spectroscopy confirmed that the important intermediates of the reaction are *COOH and *CO. The photocatalytic reduction mechanism of CO2 to CO in the BiOBr/Bi2O2CO3 type-II heterostructure was further analyzed. This study provides feasible solutions for selecting photocatalytic materials and designing facile preparation of efficient 2D/2D catalysts for photocatalytic reduction of CO2.

Enhancing photocatalytic performance of kaolin clay: an overview of treatment strategies and applications

Enhancing photocatalytic performance of kaolin clay: an overview of treatment strategies and applications

Exploring the Multifunctional aspects of SrBi2-X(CoFe2O4)XNb2O9 Nanocomposite Materials Emphasizing the Structural, Elastic, and Optical Properties

Nanocomposites of SrBi(2-X)(CF)XNb2O9 (SBNCF) (CF=CoFe2O4 for X = 0.0 to 0.5 with a step increment of 0.1) were synthesized using the hydrothermal method and characterized for their structural, morphological, elastic, and optical properties. The incorporation of CF into SrBi2Nb2O9 (SBN) resulted in hybrid composites with tailored properties. X-ray Diffraction (XRD) with Rietveld refinement analysis confirmed the formation of orthorhombic SBN and spinel CF phases. Field Emission Gun Scanning Electron Microscopy (FEG-SEM) revealed that SBN exhibits a plate-like morphology, with the incorporation of CF into the SBN matrix resulting in both plate-like and octahedral-shaped grains. The Brunauer–Emmett–Teller (BET) method was used to determine the pore radius and surface area, both of which were found to have increased, indicating an enhancement in photocatalytic performance. The presence of the constituent elements in the prepared compositions was confirmed by Energy Dispersive Spectroscopy (EDS). Fourier Transform Infrared Spectroscopy (FTIR) spectra were used to determine elastic properties, suggesting potential applications in electronic noise filtering. From Diffuse Reflectance Spectroscopy (DRS), a recognizable semiconducting behavior and band gap bowing were noticed in SBNCF nanocomposites on the obtained energy band gap values (2.20 eV - 1.56 eV) compared to the SBN host matrix (3.16 eV). The materials exhibited strong emission peaks at 470 nm, 528 nm, 584 nm, and 703 nm upon the excitation of 425 nm light using Photoluminescence (PL) spectroscopy. The white emission was predominant at room temperature in all the produced samples and the corresponding color temperature values range from 5865.93 K to 7599.05 K from the CIE diagram. The SBNCF materials are promising candidates in photocatalytic reactions and white light-emitting diodes (w-LEDs) based on their enhanced optical properties.

Enhanced Photocatalytic Activity of Direct Z‐Scheme K4Nb6O17/Carbon‐Rich Melon Heterostructures

AbstractMelon (also known as graphitic carbon nitride, g‐C3N4) holds promise for photocatalysis, but challenges such as severe charge recombination, low oxidation potential, and sluggish exciton dissociation hinder its performance. Herein, a series of carbon‐rich, melon‐based photocatalysts are synthesized via one‐pot, temperature‐induced condensation of urea with the addition of a trace amount of citric acid. The addition of citric acid enhances crystallinity, extends melon chains, increases the C/N ratio, and improves π–π layer stacking of heptazine units, thereby enhancing charge transport properties and visible‐light harvesting capacity. These carbon nitride samples are then coupled with molten salt synthesized K4Nb6O17 crystals by a straightforward self‐assembly method to construct 2D/2D heterostructure photocatalysts. Z‐scheme electron transfer from K4Nb6O17 to the melon samples is established based on their work functions and band edge positions. This efficient charge transfer in the Z‐scheme heterostructure facilitates the spatial separation of charge carriers, resulting in a nearly fivefold enhancement in photocatalytic performance compared to the individual constituents.

Facile construction of efficient WO3/V2O5 coupled g-C3N4 ternary composite photocatalyst for environmental emergent aqueous pollutant degradation: Stability, degradation reaction pathway and effect of pH evaluation.

Currently, one of the primary challenges that human society must overcome is the task of decreasing the amount of energy used and the adverse effects that it has on the environment. The daily increase in liquid waste (comprising organic pollutants) is a direct result of the creation and expansion of new companies, causing significant environmental disruption. Water contamination is attributed to several industries such as textile, chemical, poultry, dairy, and pharmaceutical. In this study, we present the successful degradation of methylene blue dye using g-C3N4 (GCN) mixed with WO3 and V2O5 composites (GCN/WO3/V2O5 ternary composite) as a photocatalyst, prepared by a simple mechanochemistry method. The GCN/WO3/V2O5 ternary composite revealed a notable enhancement in photocatalytic performance, achieving around 97% degradation of aqueous methylene blue (MB). This performance surpasses that of the individual photocatalysts, namely pure GCN, GCN/WO3, and GCN/V2O5 composites. Furthermore, the GCN/WO3/V2O5 ternary composite exhibited exceptional stability even after undergoing five consecutive cycles. The exceptional photocatalytic activity of the GCN/WO3/V2O5 ternary composite can be ascribed to the synergistic effect of metal-free GCN and metal oxides, resulting in the alteration of the band gap and suppression of charge recombination in the ternary photocatalyst. This study offers a better platform for understanding the characteristics of materials and their photocatalytic performance under visible light conditions.

Surface nitrogen defect modified crystalline carbon nitride spheres with boosted carrier dynamics for efficient solar hydrogen production

Engineering of the defective structure and crystallinity of semiconductor photocatalysts to promote carrier dynamics has attracted considerable attention. This study presents the design of surface nitrogen defect modified crystalline carbon nitride spheres (QCN) with synergistically boosted surface and bulk carrier separation through a rapid thermal treatment coupled with a flux assisted strategy. Using supramolecular self-assembled polymer as the precursor, spherical crystalline CN heterojunctions are firstly prepared by a molten salt method to improve the separation of bulk carriers. Abundant nitrogen defects are then introduced onto the surface of crystalline CN through the following quick thermal treatment in air, which can generate a higher exciton density and drive rapid migration of surface carriers by acting as effective electron sinks. Furthermore, the defect level also improves the visible light utilization and provides more active centers for reactant adsorption and activation. As a result, QCN samples exhibit excellent performance in photocatalytic hydrogen evolution, with an optimal hydrogen production rate 4.3 times higher than that of pristine bulk CN under visible light irradiation. Moreover, the photocatalytic activities of QCN are dependent on the concentration of nitrogen defects, which can be flexibly adjusted via thermal treatment temperature. Such a two-step regulation strategy combining the distinctive advantages of surface defect structure and high crystallinity is beneficial for synergistic enhancement of photocatalytic performance, and provides new insights for sustainable energy production in the future.

Engineering ZnIn2S4 with efficient charge separation and utilization for synergistic accelerate dual-function photocatalysis

Combining photocatalytic reduction with organic synthetic oxidation in the same photocatalytic redox system can effectively utilize photoexcited electrons and holes from solar to chemical energy. Here, we stabilized 0D Au clusters on the substrate surface of Zn vacancies modified 2D ZnIn2S4 (ZIS-V) nanosheets by chemically bonding Au-S interaction, forming surfactant functionalized Au/ZIS-V photocatalyst, which can not only synergistic accelerate the selective oxidation of phenylcarbinol to value-added products coupled with clean energy hydrogen production but also further drive photocatalytic CO2-to-CO conversion. An internal electric field of Au/ZIS-V ohmic junction and Zn vacancies synchronously promote the photoexcited charge carrier separation and transfer to optimized active sites for redox reactions. Compared with CO2 reduction in water and the pristine ZnIn2S4, the reaction thermodynamics and kinetics of CO2 reduction over the Au/ZIS-V were simultaneously improved about 11.09 and 45.51 times, respectively. Moreover, the photocatalytic redox mechanisms were also profoundly studied by 13CO2 isotope tracing tests, in situ electron paramagnetic resonance (in situ EPR), in situ X-ray photoelectron spectroscopy (in situ XPS), in situ diffuse reflection infrared Fourier transform spectroscopy (in situ DRIFTS) and density functional theory (DFT) characterizations, etc. These results demonstrate the advantages of vacancies coupled with metal clusters in the synergetic enhancement of photocatalytic redox performance and have great potential applications in a wide range of environments and energy.

Enhanced Photocatalytic Activities of MIL‐53(Fe)‐GO Composites via a Simple Solid‐Phase Synthesis Strategy: Increasing the Exposed Active Sites and Intimate Interfacial Contact

AbstractMIL‐53(Fe)‐GO composite photocatalysts were successfully fabricated via a simple solid‐phase synthesis strategy, and they were applied as efficient visible‐light‐driven photocatalysts for the oxidation of organic dyes and the reduction of Cr(VI). The experimental results demonstrated that MIL‐53(Fe)‐GO composites exhibit enhanced photocatalytic activities compared with the pure MIL‐53(Fe) sample. Based on the photoelectrochemical analyses, the loading of GO could enhance visible‐light absorption and accelerate the separation and transfer of charge carries, leading to the improvement of photocatalytic performance. Moreover, more intimate interfacial contact and active sites in the system could be achieved via a simple solid‐phase synthesis strategy. They could also play important role in the enhancement of photocatalytic performance. Besides, a possible photocatalytic mechanism was also investigated in detail.