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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]

In order to realize high efficiency visible-light absorption and electron–hole separation of bismuth vanadate (BVO), we synthesized carbon-doped BVO (C-BVO) with high visible-light absorption behavior. We used polyvinylpyrrolidone K-30 as a template and l-cysteine as the carbon source in a one-step hydrothermal synthesis method, and then obtained the carbon-doped BVO@multi-walled carbon nanotubes (C-BVO@MWCNT) by a two-step method. The carbon nanotubes were characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy, specific surface area, electron spin resonance, and transient photocurrent responses. The XRD analysis confirmed that all photocatalysts were in the same crystal form with a single monoclinic scheelite structure. Combining this with the other characterization results, we showed that the carbon element was successfully doped in BVO and the resulting C-BVO was successfully coupled with multi-walled carbon nanotubes. The removal ratio of rhodamine B by C-BVO@MWCNT was much higher than those by BVO and C-BVO under visible-light irradiation. Recycling experiments verified the stability of C-BVO@MWCNT, which was proved to offer excellent adsorption, strong visible-light absorption behavior, and high electron–hole separation efficiency. Such properties are expected to be useful in practical applications. [ABSTRACT FROM AUTHOR]