Photocatalysis

About: Photocatalysis is a research topic. Over the lifetime, 67088 publications have been published within this topic receiving 2145233 citations. The topic is also known as: photocatalyst.

Solar Water Splitting Using Powdered Photocatalysts Driven by Z-Schematic Interparticle Electron Transfer without an Electron Mediator

Abstract: Ru/SrTiO3:Rh photocatalyst powder for H2 evolution and varied photocatalyst powders for O2 evolution such as BiVO4 and WO3 were suspended in acidified aqueous solutions, resulting in showing activities for water splitting into H2 and O2 in a stoichiometric ratio without an electron mediator under visible light irradiation. The photocatalytic activities were dependent on pH. The highest activity was obtained at pH 3.5. An optical microscope observation of the aqueous suspension containing Ru/SrTiO3:Rh and BiVO4 powders at pH 3.5 revealed that these powders aggregated with suitable contact. The condition of Rh doped in SrTiO3 also affected strongly the photocatalytic activity and quenching of the photoluminescence of BiVO4. The high photocatalytic activity was obtained and the luminescence was remarkably quenched, when SrTiO3:Rh containing Rh species with reversible redox properties was used and mixed. These results indicated that the photocatalytic water splitting and quenching of the photoluminescence occ...

Photocatalytic reduction of CO2 into hydrocarbon solar fuels over g-C3N4–Pt nanocomposite photocatalysts

Abstract: Photocatalytic reduction of CO2 into renewable hydrocarbon fuels is an alternative way to develop reproducible energy, which is also a promising way to solve the problem of the greenhouse effect. In this work, graphitic carbon nitride (g-C3N4) was synthesized by directly heating thiourea at 550 °C and then a certain amount of Pt was deposited on it to form g-C3N4–Pt nanocomposites used as catalysts for photocatalytic reduction of CO2 under simulated solar irradiation. The main products of photocatalysis were CH4, CH3OH and HCHO. The deposited Pt acted as an effective cocatalyst, which not only influenced the selectivity of the product generation, but also affected the activity of the reaction. The yield of CH4 first increased upon increasing the amount of Pt deposited on the g-C3N4 from 0 to 1 wt%, then decreased at 2 wt% Pt loading. The production rates of CH3OH and HCHO also increased with the content of Pt increasing from 0 to 0.75 wt% and the maximum yield was observed at 0.75 wt%. The Pt nanoparticles (NPs) could facilitate the transfer and enrichment of photogenerated electrons from g-C3N4 to its surface for photocatalytic reduction of CO2. At the same time, Pt was also used a catalyst to promote the oxidation of products. The transient photocurrent response further confirmed the proposed photocatalytic reduction mechanism of CO2. This work indicates that the deposition of Pt is a good strategy to improve the photoactivity and selectivity of g-C3N4 for CO2 reduction.

Characterization and photocatalytic mechanism of nanosized CdS coupled TiO2 nanocrystals under visible light irradiation

Abstract: Nanosized CdS coupled TiO2 nanocrystals were prepared by a microemulsion-mediated solvothermal method at relatively low temperatures The prepared samples were characterized by X-ray photoelectron spectroscopy (XPS), BET surface area analysis, X-ray diffraction (XRD), UV–vis absorption spectroscopy (UV–vis), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) It was found that the CdS coupled TiO2 materials consisted of uniform anatase TiO2 of 6–10 nm with highly dispersed cubic phase CdS nanocrystals The prepared samples exhibit strong visible light absorption at about 550 nm Meanwhile, they have high surface area in the range of 156–263 m2 g−1 and mesoporous character with the average pore diameter of ca 50–65 nm The coupling between the (1 0 1) crystal planes of anatase and (1 1 1) crystal planes of CdS was observed in the HRTEM image Ti3+ signal was observed in the electron paramagnetic resonance (EPR) spectrum of CdS coupled TiO2 nanocrystals under visible light irradiation It provided the evidence of an effective transfer of photo-generated electrons from the conduction band of CdS to that of TiO2 As expected, the nanosized CdS sensitized TiO2 nanocrystal materials showed enhanced activity in the oxidation of methylene blue in water or nitric oxide in air under visible light irradiation The mechanism of photocatalysis on CdS coupled TiO2 nanocrystals under visible light is also discussed