AUTHOR=Yuan Xiuhua , Sun Xia , Zhou Huawei , Zeng Suyuan , Liu Bingxin , Li Xia , Liu Dong 

TITLE=Free-Standing Electrospun W-Doped BiVO4 Porous Nanotubes for the Efficient Photoelectrochemical Water Oxidation

JOURNAL=Frontiers in Chemistry

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.00311

DOI=10.3389/fchem.2020.00311

ISSN=2296-2646

ABSTRACT=<p>While bismuth vanadate (BiVO<sub>4</sub>) has emerged as a promising photoanode in solar water splitting, it still suffers from poor electron-hole separation and electron transport properties. Therefore, the development of BiVO<sub>4</sub> nanomaterials that enable performing high charge transfer rate at the interface and lowering charge recombination is urgent needed. Herein, cobalt borate (Co-B) nanoparticle arrays anchored on electrospun W-doped BiVO<sub>4</sub> porous nanotubes (BiV<sub>0.97</sub>W<sub>0.03</sub>O<sub>4</sub>) was prepared for photoelectrochemical (PEC) water oxidation. One-dimensional, free-standing and porousBiV<sub>0.97</sub>W<sub>0.03</sub>O<sub>4</sub>/Co-B nanotubes was synthesized through electrospun and electrodeposition process. BiV<sub>0.97</sub>W<sub>0.03</sub>O<sub>4</sub>/Co-B arrays exhibit a unique self-supporting core-shell structure with rough porous surface, providing abundant conductive cofactor (W) and electrochemically active sites (Co) exposed to the electrolyte. When applied to PEC water oxidation. BiV<sub>0.97</sub>W<sub>0.03</sub>O<sub>4</sub>/Co-B modified FTO electrode displays high incident photon-to-current conversion efficiency (IPCE) of 33% at 405 nm (at 1.23 V vs. RHE) and its photocurrent density is about 4 times to the pristine nanotube. The higher PEC water oxidation properties of BiV<sub>0.97</sub>W<sub>0.03</sub>O<sub>4</sub>/Co-B porous nanotubes may be attributed to the effectively suppress the electron-hole recombination at electrolyte interface due to its self-supporting core-shell structure, the high electrocatalytic activity of Co and the good electrical conductivity of BiV<sub>0.97</sub>W<sub>0.03</sub>O<sub>4</sub> arrays. This work offers a simple preparation strategy for the integrated Co-B nanoparticle with BiV<sub>0.97</sub>W<sub>0.03</sub>O<sub>4</sub> nanotube, demonstrating the synergistic effect of co-catalysts for PEC water oxidation.</p>