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Photocatalytic Activation of C-H Bonds by Spatially Controlled Chlorine and Titanium on the Silicate Layer
摘要： Owing to the economic and environmental benefits, photocatalytic organic transformation via C-H activation is a crucially important, while still challenging area. We report photocatalytic process for partial cyclohexane oxidation with enhanced catalytic activity that exploits chlorine and titanium atoms spatially arranged on a silica substrate. Silica-based catalysts bearing grafted titanium that effectively interacts with photochemically adsorbed chlorine were prepared. The catalysts were synthesized by reacting a layered silicate with titanium(IV) acetylacetonate and subsequent chlorination treatment. Characterization by a variety of techniques revealed that the organic ligand of the titanium species that is grafted onto the silicate layer surface is converted into chlorine while maintaining its coordination state. However, upon subsequent hydration, the chlorine existed as HCl. We investigated the performance of the catalyst for the production of cyclohexanol and cyclohexanone from cyclohexane with molecular oxygen under solar light irradiation. The chlorinated layered silicate photocatalyst exhibited a remarkably high production rate (0.7 mmol g-1 h-1) and large amount of product formed (0.8 mmol), while the over-oxidation of cyclohexane was inhibited. The enhanced catalytic ability could be explained by the presence of a radical mediator (chlorine) located at a position neighboring an isolated titanium atom. The high surface density of these active species (both titanium and chlorine) on the silicate layer provided suitable electron transfer to form chlorine radicals.
关键词： Photocatalysis,partial oxidation,C-H activation,KA oil,layered silicate,titanosilicate,chlorine,cyclohexane oxidation
更新于2025-11-19 16:51:07
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Cu3MS4 (M=V, Nb, and Ta) and their solid solutions with sulvanite structure for photocatalytic and photoelectrochemical H2 evolution under visible light irradiation
摘要： Solid solutions with a sulvanite structure between Cu3VS4 and either Cu3NbS4 or Cu3TaS4 (Cu3Nb1-xVxS4, Cu3Ta1-xVxS4) were successfully prepared by a solid-state reaction. Their band gaps were 1.6–1.7 eV corresponding to the absorption of a wide range of visible light. Ru-cocatalyst loaded Cu3MS4 (M=V, Nb, Ta), Cu3Nb1-xVxS4, and Cu3Ta1-xVxS4 showed photocatalytic activities for sacrificial H2 evolution under visible light irradiation. Most solid solutions showed better activities than the single Cu3MS4 (M=V, Nb, Ta). Cu3MS4 (M=V, Nb), Cu3Nb1-xVxS4, and Cu3Ta1-xVxS4 also functioned as a photoelectrode and gave cathodic photocurrents under visible light irradiation, indicating a p-type semiconductor character. Cu3Nb0.9V0.1S4 showed the best photocatalytic and photoelectrochemical performances. When Ru-loaded Cu3Nb0.9V0.1S4 was used as a photocathode with a CoOx-loaded BiVO4 photoanode, photoelectrochemical water splitting proceeded under simulated sunlight irradiation without an external bias.
关键词： Energy conversion,Water splitting,Heterogeneous catalysis,Photocatalysis
更新于2025-11-19 16:51:07
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Reconstructing Dual‐Induced {0 0 1} Facets Bismuth Oxychloride Nanosheets Heterostructures: An Effective Strategy to Promote Photocatalytic Oxygen Evolution
摘要： Sunlight-driven photocatalytic water splitting to generate oxygen (O2) is a promising approach for utilizing solar energy. Herein, direct Z-scheme heterostructure photocatalysts composed of ultrathin Bi3O4Cl and BiOCl nanosheets are rationally fabricated via alkaline chemical etching and solvent exfoliation for O2 evolution under visible light. With AgNO3 and FeCl3 as the electron scavenger, the optimized ultrathin Bi3O4Cl/BiOCl exhibits prominent photocatalytic activity for O2 production under visible-light illumination and the production rate (58.6 μmol g?1 h?1) is much higher than the nanocrystal heterostructure (28.5 μmol g?1 h?1). This ultrathin heterostructure system can efficiently transfer the electrons, which leads to a considerable improvement in the photocatalytic performance. Due to the suitable band edge potentials and the intense electronic interaction between two-dimensional (2D) Bi3O4Cl and 2D BiOCl, as confirmed by theoretical computations, photoluminescence, and photoelectricity tests, the ultrathin heterojunction with an internal electric field has a highly remarkable charge transfer. The intimate interface contact and {0 0 1} facets effect promote the high photocatalytic performance of the ultrathin Bi3O4Cl/BiOCl heterostructure.
关键词： remarkable charge transfer,ultrathin Bi3O4Cl/BiOCl heterostructure,facets effect,photocatalysis
更新于2025-11-19 16:51:07
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Constructing highly dispersed 0D Co3S4 quantum dots/2D g-C3N4 nanosheets nanocomposites for excellent photocatalytic performance
摘要： Herein, 0D metal sulfide quantum dots/2D g-C3N4 nanosheets (Co3S4/CNNS) nanocomposites are synthesized by a two-step method, including the ways of in-situ deposition and water bath. The highly dispersed Co3S4 quantum dots (particle size is 2-4 nm) are evenly and tightly fixed on CNNS, which can be used as co-catalyst to effectively replace noble metals to improve the photocatalytic properties of CNNS. Co3S4/CNNS-900 has the apparent quantum efficiency, which is up to 7.85 % at 400 nm. At the same times, the H2 evolution rate of Co3S4/CNNS-900 is 20536.4 μmol·g-1·h-1, which is 555 times than CNNS.
关键词： g-C3N4,photocatalysis,Co3S4
更新于2025-11-19 16:46:39
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Facile Synthesis and Enhanced Visible-Light Photocatalytic Activity of Novel p-Ag3PO4/n-BiFeO3 Heterojunction Composites for Dye Degradation
摘要： In this work, Ag3PO4 microparticles were decorated onto the surface of BiFeO3 microcuboids through a precipitation method to obtain p-Ag3PO4/n-BiFeO3 heterojunction composites. The composites were employed for the degradation of acid orange 7 (AO7) under visible-light irradiation. It is found that the composites exhibit much higher photocatalytic efficiency than bare BiFeO3. Meanwhile, the intrinsical visible-light-driven photocatalytic activity of Ag3PO4/BiFeO3 composites was further confirmed by the degradation of phenol. In addition, the photo-Fenton-like catalysis property of the composite was also evaluated. The photocurrent analysis indicates that the combination of BiFeO3 with Ag3PO4 leads to the inhibition of recombination of photoinduced electrons and holes. The obvious enhancement in the photocatalytic activity of the composite is mainly ascribed to the efficient photogenerated charge separation and interfacial charge migration caused by the formation of Ag3PO4/BiFeO3 p-n heterojunctions.
关键词： BiFeO3,Photocatalysis,Heterojunction,Ag3PO4
更新于2025-11-19 16:46:39
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Photocatalytic and Photo-Fenton Catalytic Degradation Activities of Z-Scheme Ag2S/BiFeO3 Heterojunction Composites under Visible-Light Irradiation
摘要： Z-scheme Ag2S/BiFeO3 heterojunction composites were successfully prepared through a precipitation method. The morphology and microstructure characterization demonstrate that Ag2S nanoparticles (30–50 nm) are well-decorated on the surfaces of polyhedral BiFeO3 particles (500–800 nm) to form Ag2S/BiFeO3 heterojunctions. The photocatalytic and photo-Fenton catalytic activities of the as-derived Ag2S/BiFeO3 heterojunction composites were evaluated by the degradation of methyl orange (MO) under visible-light irradiation. The photocatalytic result indicates that the Ag2S/BiFeO3 composites exhibit much improved photocatalytic activities when compared with bare Ag2S and BiFeO3. The optimum composite sample was observed to be 15% Ag2S/BiFeO3 with an Ag2S mass fraction of 15%. Furthermore, the addition of H2O2 can further enhance the dye degradation efficiency, which is due to the synergistic effects of photo- and Fenton catalysis. The results of photoelectrochemical and photoluminescence measurements suggest a greater separation of the photoexcited electron/hole pairs in the Ag2S/BiFeO3 composites. According to the active species trapping experiments, the photocatalytic and photo-Fenton catalytic mechanisms of the Ag2S/BiFeO3 composites were proposed and discussed.
关键词： polyhedral BiFeO3 particles,photo-Fenton catalysis,Ag2S nanoparticles,photocatalysis,Z-scheme Ag2S/BiFeO3 heterojunction
更新于2025-11-19 16:46:39
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A magnetically recoverable CaTiO<sub>3</sub>/reduced graphene oxide/NiFe<sub>2</sub>O<sub>4</sub> nanocomposite for the dye degradation under simulated sunlight irradiation
摘要： In this work, ternary CaTiO3/reduced graphene oxide (rGO)/NiFe2O4 nanocomposite was successfully prepared using polyacrylamide gel route followed by hydrothermal method. It is observed that NiFe2O4 and CaTiO3 nanoparticles are assembled on the surface of rGO. Furthermore, the formation of chemical bonding between the nanoparticles and rGO is confirmed. The photocatalytic activities of the samples were evaluated through the degradation of methylene blue and rhodamine B under the simulated sunlight irradiation. The results indicate that the ternary nanocomposite exhibits remarkable enhanced photocatalytic activity compared with bare CaTiO3 and NiFe2O4. In this nanocomposite, the photogenerated electrons of CaTiO3 and NiFe2O4 can be captured by rGO, leading to an increased separation and availability of electrons and holes for the photocatalytic reaction. Moreover, this nanocomposite exhibits obvious ferromagnetism and can be readily recovered by external magnetic field. The recycling photocatalytic experiment demonstrates that the nanocomposite possesses good photocatalytic reusability.
关键词： Nanocomposite,CaTiO3,Graphene,NiFe2O4,Photocatalysis
更新于2025-11-19 16:46:39
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Ag1.69Sb2.27O6.25 coupled carbon nitride photocatalyst with high redox potential for efficient multifunctional environmental applications
摘要： Most photocatalysts cannot exhibit high efficiency to remove both gaseous and aqueous pollutants due to the limitation of redox potential and chemical property of photocatalyst itself, which will hinder the broad application of the photocatalysts. Herein, silver antimonite (Ag1.69Sb2.27O6.25) is coupled with polymeric carbon nitride (CN) as efficient photocatalyst for various environmental remediation reactions. The UV-visible light adsorption spectra, valence band X-ray photoelectron spectroscopy, and electron spin resonance spectra of different photogenerated radicals have confirmed that the transfer of electrons and holes have high redox potential to produce reactive O2?- and OH?. The Ag1.69Sb2.27O6.25 coupled CN photocatalyst produces much enhanced activity in removing various pollutants in that it exhibits about 15 folds as CN in mineralizing gaseous isopropanol into CO2, 5 folds as Ag1.69Sb2.27O6.25 in destructing aqueous oxytetracycline hydrochloride, and 10 folds as Ag1.69Sb2.27O6.25 in decoloring methylene blue under the irradiation of visible light. Control experiments in presence of scavengers p-benzoquinone and coumarin have revealed that both electrons and holes in heterojunctions participate in degradation reactions, which induce the much enhanced photocatalytic activity in removing pollutants. This study provides a facile strategy to design photocatalysts for efficient multifunctional environmental applications.
关键词： Heterojunction,Photocatalysis,Photodegradation,Silver antimonites,environmental remediation
更新于2025-11-14 17:04:02
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ZIF-8 derived hollow CuO/ZnO material for study of enhanced photocatalytic performance
摘要： Tetracycline hydrochloride (TC) is a broad-spectrum antibiotic extensively used in medical and veterinary fields. However, its excess harms the environment and human health. Recently, construction of CuO/ZnO heterojunctions has a very good effect in the treatment of organic matter in water. In this study, we used zeolite imidazolate framework (ZIF-8) as initial material to synthesize porous and hollow CuO/ZnO photocatalysts for catalytic degradation of TC. The results show that the synthesized CuO/ZnO has the characteristics of porous hollow polyhedron when the molar ratio of Cu and Zn is 0.1. Obviously, photocatalytic degradation rate was better comparing to CuO/ZnO nanoparticles as well as pure ZnO and CuO particles, respectively, which could reach 87% at 60min under visible light (λ>420 nm) and has good stability. Porous hollow CuO/ZnO composites are very promising for effective and environmentally friendly degradation of tetracycline hydrochloride in water.
关键词： Photocatalysis,Tetracycline hydrochloride,Zeolite imidazolate frameworks (ZIF-8),Hollow CuO/ZnO
更新于2025-11-14 17:04:02
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Enhanced photoelectrochemical performance of Zn2SnO4N by interstitial N induced the build-in polarization electric field
摘要： Highly active Zn2SnO4N photocatalysts were successfully prepared by the one-step microwave-assisted solvothermal method. N heteroatoms were introduced into Zn2SnO4 by occupying the interstitial sites, inducing the formation of the build-in polarization electric field and the impurity level which was advantageous to promote the separation and the migration of photoinduced electron-hole pairs. As a result, the as-prepared Zn2SnO4N exhibited improved the photoelectrochemical properties and the photodegradation rate of RhB over Zn2SnO4N had been demonstrated to increase 3.3 times compared to that of pure Zn2SnO4. Under the effect of the built-in electric field, the impurity level served as a springboard for electron transition rather than a recombination center, which caused the enhancing photocatalytic performance. The finding may provide a new insight into understanding the mechanism of doping modification.
关键词： N-doped,Zn2SnO4,Build-in electric field,Photocatalysis,Impurity level
更新于2025-11-14 17:04:02