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To achieve an efficient visible-light absorption and degradation of bismuth vanadate (BiVO), in this paper, a carbon-doped (C-doped) nanosheets monoclinic BiVO (m-BiVO), with thicknesses within 19.86 ± 8.48 nm, was synthesized using polyvinylpyrrolidone K-30 (PVP) as a template and l-carbonic as the carbon source by one-step hydrothermal synthesis method. This C-doped BiVO in three-dimensional (3D) hierarchical structure enjoys high visible-light photocatalytic property. The samples were characterized using x-ray diffraction, scanning electron microscope, Raman spectra, energy dispersive spectrometer, transmission electron microscope, x-ray photoelectron spectroscopy, UV-Vis diffused reflectance spectroscopy, specific surface area, electron spin resonance, and transient photocurrent response, photoluminescence spectra, and incident-photon-to-current conversion efficiency, respectively. What is more, we studied the C-doping effect on the band-gap energy of BiVO based on First-principles. X-ray diffraction analysis showed that all photocatalysts were in the same single monoclinic scheelite structure. According to the other characterization results, the element C was successfully doped in BiVO, resulting in the 3D hierarchical structure of C-doped BiVO (P-L-BiVO). We speculated that it could be the directional coalescence mechanism by which the l-cysteine promoted the two-dimensional growth and C-doping process of BiVO, thus leading to the formation of nanosheets which were then promoted into 3D self-assembly by PVP and the shortening of the band gap. Among all samples, P-L-BiVO can make the highest removal ratio of rhodamine B under visible-light irradiation. The stability of P-L-BiVO was verified by recycle experiments. It showed that P-L-BiVO had strong visible-light absorption behavior and high electron-hole separation efficiency and stability, making a significant advantage in actual situation. [ABSTRACT FROM AUTHOR]

SrTiO 3 -reduced graphene oxide (SrTiO 3 -RGO) composites were synthesized via a facile one pot hydrothermal process. This was achieved by decorating graphene oxide (GO) layers with Ti(OBu) 4 and Sr(NO 3 ) 2 as starting materials followed by hydrothermal synthesis, which converts the SrTiO 3 particles with a diameter of 87–200 nm on the RGO surface, without using strong reducing agents. The as-prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), electrochemical impedance spectra (EIS), and photocurrent analysis. SrTiO 3 particles were shown to be grown homogeneously on the RGO sheets with close interfacial contacts. The photocatalytic hydrogen evolution activities of the SrTiO 3 and SrTiO 3 -RGO composites were contrasted. Compared to SrTiO 3 , SrTiO 3 -RGO composites showed much higher photocatalytic hydrogen production activity under UV light irradiation. The SrTiO 3 -0.8%RGO composite showed the highest photocatalytic H 2 evolution activity. PL, EIS and photocurrent analysis were used to elucidate the mechanism that the enhancement of photocatalytic hydrogen evolution activity over the SrTiO 3 -RGO composites is attributed to the reduction of the photogenerated electron-hole recombination. [ABSTRACT FROM AUTHOR]

Abstract: Novel visible-light-driven Sb2O3/WO3 photocatalysts were prepared by a hydrothermal synthesis followed by heat treatment, and characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), BET surface area, Fourier transform infrared spectroscopy (FT-IR) and photoluminescence spectra (PL). The photocatalytic activities of Sb2O3/WO3 photocatalysts were evaluated by the rhodamine B degradation using a LED lamp as visible light irradiation. Compared with pure WO3 and Sb2O3, the significantly enhanced photocatalytic activities of the Sb2O3/WO3 composite particles are attributed to the decrease of the recombination rate of photoinduced electron–hole pairs due to the coupling of Sb2O3 and WO3 within the composite nanoparticles. Studies of Sb2O3/WO3 composites indicate that one approach to design composite materials with enhanced photocatalytic performance is through coupling Sb2O3 with WO3, which the lowest energy states for electrons and holes are in different semiconductors. [Copyright &y& Elsevier]