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Tuning CuOx-TiO2 interaction and photocatalytic hydrogen production of CuOx/TiO2 photocatalysts via TiO2 morphology engineering
摘要： CuOx/TiO2 photocatalysts prepared with anatase TiO2 nanocrystals exposing different types of facets as supports were examined for photocatalytic H2 production in methanol/water solution under simulated solar light. Catalyst structures were characterized by XRD, HRTEM, XPS, UV–vis, EPR, PL, H2-TPR and CO chemisorption. Enhanced photocatalytic H2 productions of CuOx/TiO2 photocatalysts followed an order of CuOx/TiO2-{001} > CuOx/TiO2-{100} > CuOx/TiO2-{101}. TiO2 facets were found to strongly affect the CuOx-TiO2 interaction and structures of CuOx/TiO2 photocatalysts. Cu2O-TiO2 interaction in CuOx/TiO2-{001} photocatalyst is the strongest, resulting in the highest Cu2O dispersion and density of Cu2O-TiO2 heterojunctions active in photocatalytic H2 production. The results add insights into morphology engineering as an effective strategy to tune structures and photocatalytic activity of TiO2-based composite photocatalysts.
关键词： metal-support interaction,water reduction,charge separation,photocatalysis,facet
更新于2025-09-04 15:30:14
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Design of spatially separated Au and CoO dual cocatalysts on hollow TiO2 for enhanced photocatalytic activity towards the reduction of CO2 to CH4
摘要： Photocatalytic reduction of CO2 to solar fuels has been considered as a promising route to solve the energy crisis and environmental issues. Herein, the spatially separated CoO and Au dual cocatalysts are used as the hole and electron collectors, which are loaded on the internal and external surface of TiO2 hollow sphere (THS), respectively (denoted as Aux@THS@CoO). It is found that the Au nanoparticle and Co species are homogenous deposited on the surface of THS without doping. DRS results show that the photoabsorption performances of THS are enhanced obviously in the visible light region. XPS analysis reveals that an internal electric field is constructed, which could promote the separation of photoinduced charge carriers. Subsequently, Au2.0@THS@CoO displays the highest photocurrent density compared with the counterparts. Furthermore, the results of CO2 adsorption, ESR spectra and in-situ FTIR spectra show the high adsorption capacity of CO2 on the sample and the chemisorption of CO2 on the oxygen defects of THS conversed into the active intermediate CO2-. As a result, Au2.0@THS@CoO presents a remarkably enhanced photocatalytic activity for the reduction of CO2 with H2O in CH4. The optimal activity of the catalyst is 13.3 μmol h-1 g-1, which is 60 times higher than that of THS. In addition, in-situ FTIR spectra also suggest that H2O participates in the reaction as electron donator and hole scavenger during the photocatalysis process. Finally, a possible photocatalytic process has also been proposed.
关键词： Photocatalysis,Synergistic effect,Spatial separation,Dual cocatalysts,CO2 reduction
更新于2025-09-04 15:30:14
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One-step synthesis of petals-like graphitic carbon nitride nanosheets with triazole defects for highly improved photocatalytic hydrogen production
摘要： Reaction atmospheres during graphitic carbon nitride preparation can have a significant influence on the chemical composition and structure of the material, subsequently improving the photocatalytic activity. However, it is still a challenge to introduce an atmosphere by one-step heat-treated method to synthesis graphitic carbon nitride without additive gases. Herein, we developed a new one-step method to gather a variety of gases for preparing petals-like graphitic carbon nitride nanosheets (CNeC), such as CO(g), NH3(g) and H2O(g). NH3(g) and H2O(g) are respectively derived from melamine-cyanuric acid supermolecule during pyrolysis. The petals-like CNeC with more triazole defects (Nc) significantly increases the separation efficiency and the mobility of photogenerated photo-induced electron-hole pairs. Compared with the g-C3N4 calcined under nitrogen atmosphere (CNeN), CNeC has smaller grain, higher porosity with larger surface area, and remarkably longer lifetime of charge carriers. As expected, the product CNeC exhibited a hydrogen evolution rate of 1334 mmol g?1 h?1 under visible-light irradiation, which was 2.8 times higher activity than CNeN, as well as higher than most of the reported bulk g-C3N4.
关键词： Photocatalysis,g-C3N4,Triazole defects,Multiple gases,Hydrogen evolution
更新于2025-09-04 15:30:14
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CQDS preluded carbon-incorporated 3D burger-like hybrid ZnO enhanced visible-light-driven photocatalytic activity and mechanism implication
摘要： Environmentally friendly photodegradation of refractory pollutants utilizing semiconductor photocatalysis evolution exhibits satisfactory efficiency and low energy consumption, but some of its unbefitting band position largely limits practical applications. The controllable band structure tuning via coupling low-dimensional materials with enormous potential in semiconductor photocatalysis, notably attractive carbon quantum dots (CQDs) induced for a better utilization of low-energy photoexcitation of promising inherent optical properties and photocatalytic performance on organic pollutant degradation. Here, a CQDs modified ZnO hybrid materials was synthesized and the CQDs preluded carbon-incorporated burger-like ZnO nanoparticles clusters were presented thus demonstrated a specific doping-effect. The dispersity improved by loading halloysite nanotube (HNTs) for efficiently photocatalytic activity enhancement. Furthermore, the band structure, excitation and photocatalytic reactive oxygen species (ROS) generation were detected to reveal the photochemical properties and plausible mechanism of CQDs hybrid nanomaterials system. It is observed that the superoxide radical (O2?), and singlet oxygen (1O2) are the principal ROS agents under UV–vis excitations. This work not only displays a CQDs modified system of expanding photo-response range to visible light but also throws a way for quantum elemental incorporated on the influence of band-tuning for semiconductor- dominated photocatalysts.
关键词： Carbon-incorporated,Tetracycline,Photocatalysis,Carbon quantum dots,ZnO
更新于2025-09-04 15:30:14
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Effect of Ce and Mn co-doping on photocatalytic performance of sol-gel TiO2
摘要： Co-doped titanium dioxide was synthesized by doping with manganese (Mn) and cerium (Ce) through a sol-gel method for the degradation of diclofenac (DCF). The synthesized products were successfully characterized by X-ray diffraction (XRD), Raman spectroscopy, Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Nitrogen physisorption at 77 K, X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance (UV-DRS), photoluminescence spectroscopy (PL) and total organic carbon (TOC). It was shown that co-doping increased the specific surface area, improved the visible light absorption and extended the lifetime of photogenerated charge carriers. Furthermore, the results of the photocatalytic experiments show that the photodegradation rate of diclofenac can be approached by pseudo first-order kinetics and it followed the Langmuir-Hinshelwood model very well. The co-doped catalyst with 0.6 % Mn and 1 % Ce molar ratios appeared to be the most photoactive catalyst with 94 % of DCF removal and an apparent rate constant of 0.012 min-1.
关键词： Photocatalysis,co-doping,manganese and cerium,titanium dioxide,diclofenac
更新于2025-09-04 15:30:14
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Exploration of charge carrier delocalization in the iron oxide/CdS type-II heterojunction band alignment for enhanced solar-driven photocatalytic and antibacterial applications
摘要： Recyclable magnetic photocatalysts of iron oxide (IO)/CdS core/shell nanocrystals (CSNCs) were prepared by a facile sequential one-pot method using 3, 3'-thiobispropanoic acid (TDP) as a bridge. The CSNCs showed redshift in absorption edge, decrease in the optical band gap, reduced exciton decay rates and increment in particle size. Quenching studies have been employed to understand the position of the electron/hole wave-functions at the IO/CdS interface. Antimicrobial tests have also been performed using broth tube dilution and disc diffusion methods against S. aureus. Additionally, photocatalytic properties of IO/CdS CSNCs have been evaluated for the decomposition of xylenol blue. In comparison with CdS quantum dots (QDs) and iron oxide nanoparticles (IONPs), the IO/CdS CSNCs showed improved photocatalytic and bactericidal activities. Finally, levels of oxidative damage to proteins and lipids were evaluated.
关键词： Photocatalysis,Wave-function engineering,Advanced oxidation process,Iron oxide/CdS nanocrystals,Photocatalytic bacterial inactivation
更新于2025-09-04 15:30:14
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WS2 nanodots-modified TiO2 nanotubes to enhance visible-light photocatalytic activity
摘要： WS2 nanodots-modified TiO2 nanotubes (TNT/WND) composites were fabricated via one-pot hydrothermal method for the first time. The physical and photophysical properties of the as-prepared photocatalysts were characterized by XRD, TEM, HRTEM, BET, UV-vis, and PL. The results demonstrated that WS2 nanodots have been successfully anchored on the inner wall of TiO2 nanotubes. TNT/WND composites showed excellent photocatalytic activity toward photodegradation of rhodamine B (RhB) under visible-light, which mainly attributed to the synergistic effect from relative low recombination rate of the photogenerated electron-hole pairs and high specific surface area.
关键词： Semiconductors,Photocatalysis,WS2 nanodots,Structural,TiO2 nanotubes,Nanocomposites
更新于2025-09-04 15:30:14
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Tetrathiafulvalene Scaffolds Based Sensitizer on Hierarchical Porous TiO <sub/>2</sub> : Efficient Light Harvesting Material for Hydrogen Production
摘要： In this work, a photochemical device that contains thioalkyl substituted tetrathiafulvalene dyes and hierarchical porous TiO2, has been designed and successfully employed in visible light-driven hydrogen production. The design strategy boost up the desirable photophysical properties of the catalysts and well supported from the optical, electrochemical and computational studies. The introduction of thioalkyl substituted tetrathiafulvalene dyes as light harvesting sensitizers onto the porous TiO2 triggers unprecedented high rate of hydrogen evolution. This study focuses on the role of thiafulvalene scaffold which can promote ultrafast interfacial electron injection from excited state dye into the hierarchical porous TiO2 conduction band. The purposeful construction of this integrated composite G3T3 (dye content 1.0 μmol in 10 mg Pt-TiO2 composite) significantly increases the hydrogen production rate of 24560 μmol.h-1g-1 cat with high apparent quantum yield (AQY) ~ 41%. In the study, both sensitizers absorption onset extends up to 500 nm in solution and 600 nm on hierarchical porous TiO2. Density functional theory (DFT) in the present study described that the HOMO levels are delocalized on anthracene as well as tetrathiafulvalene donor units, and LUMO covers on to the carboxylate anchoring group in both dyes. This study unveiled first time that a tetrathiafulvalene scaffolds in porous TiO2 attributes to positive synergistic effects in hydrogen production.
关键词： Tetrathiafulvalene,Hydrogen Production,Photocatalysis,Hierarchical Porous TiO2,Visible Light
更新于2025-09-04 15:30:14
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Selective Ferroelectric BiOI/Bi4Ti3O12 Heterostructures For Visible-light-driven Photocatalysis
摘要： Ferroelectric-photocatalyst/photocatalyst heterojunctions have very attractive photocatalytic activities. Beside enhanced charge carrier separation due to their internal electric fields, charge transfer could be even further enhanced by designing the heterojunction interface. In this work, the polarization-adsorption interaction that exists in ferroelectric materials was employed for successful deposition of BiOI on specific surfaces of Bi4Ti3O12 plates in the dark at room temperature, where the positively polarized region was found. The crystal structure, morphology, and composition of samples were confirmed by X-ray diffraction, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy, respectively. Higher photocatalytic activity was achieved by the use of heterojunctions, with the reason behind the enhancement of activity confirmed to be the modified band structure, which contributed to the transfer of photoelectrons from Bi4Ti3O12 to BiOI, the increased visible light absorption, the increased active site area of positively polarized Bi4Ti3O12, and the elimination of the screening layer, which contributes impedance in charge transfer.
关键词： Visible-light-driven,Photocatalysis,Heterostructures,BiOI/Bi4Ti3O12,Ferroelectric
更新于2025-09-04 15:30:14
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Metal–Organic Frameworks for Photocatalysis and Photothermal Catalysis
摘要： To meet the ever-increasing global demand for energy, conversion of solar energy to chemical/thermal energy is very promising. Light-mediated catalysis, including photocatalysis (organic transformations, water splitting, CO2 reduction, etc.) and photothermal catalysis play key roles in solar to chemical/thermal energy conversion via the light?matter interaction. The major challenges in traditional semiconductor photocatalysts include insufficient sunlight utilization, charge carrier recombination, limited exposure of active sites, and particularly the difficulty of understanding the structure?activity relationship. Metal?organic frameworks (MOFs), featuring semiconductor-like behavior, have recently captured broad interest toward photocatalysis and photothermal catalysis because of their well-defined and tailorable porous structures, high surface areas, etc. These advantages are beneficial for rational structural modulation for improved light harvesting and charge separation as well as other effects, greatly helping to address the aforementioned challenges and especially facilitating the establishment of the structure?activity relationship. Therefore, it is increasingly important to summarize this research field and provide in-depth insight into MOF-based photocatalysis and photothermal catalysis to accelerate the future development.
关键词： Charge separation,Photocatalysis,Light harvesting,Solar energy conversion,Photothermal catalysis,Metal?organic frameworks
更新于2025-09-04 15:30:14