Monoclinic bismuth vanadate (BiVO4) is an attractive material with which to fabricate photoanodes due to its suitable band structure and excellent photoelectrochemical (PEC) performance. However, the poor PEC stability originating from its severe photo-corrosion greatly restricts its practical applications. In this paper, pristine and Mo doped BiVO4ceramics were prepared using the spark plasma sintering (SPS) method, and their photoelectrochemical properties as photoanodes were investigated. The as-prepared 1% Mo doped BiVO4ceramic (Mo-BVO (C)) photoanode exhibited enhanced PEC stability compared to 1% Mo doped BiVO4films on fluorine doped Tin Oxide (FTO) coated glass substrates (Mo-BVO). Mo-BVO (C) exhibited a photocurrent density of 0.54 mA/cm2and remained stable for 10 h at 1.23 V vs. reversible hydrogen electrode (RHE), while the photocurrent density of the Mo-BVO decreased from 0.66 mA/cm2to 0.11 mA/cm2at 1.23 V vs. RHE in 4 h. The experimental results indicated that the enhanced PEC stability of the Mo-BVO (C) could be attributed to its higher crystallinity, which could effectively inhibit the dissociation of vanadium in BiVO4during the PEC process. This work may illustrate a novel ceramic design for the improvement of the stability of BiVO4photoanodes, and might provide a general strategy for the improvement of the PEC stability of metal oxide photoanodes.Keywords:BiVO4photoanode;photoelectrochemical stability;spark plasma sintering (SPS);ceramics
Lili Gao,Xuefeng Long,Shenqi Wei,Chenglong Wang,Tong Wang,Feng Li,Yiping Hu,Jiantai Ma,Jun Jin
BiVO 4 is largely restricted by its intrinsic poor electron mobility and sluggish surface reaction. Aiming at eliminating the deficiency of BiVO 4 , we assemble a novel composite photoanode through simultaneous bulk and surface modification. In detail, controllable Mo doping is manipulated through a spin-coating method, and AgVO 3 nanoparticles are loaded by successive ionic layer adsorption and reaction (SILAR) process. The as-prepared photoanode boosts the photocurrent density by 7 folds at 1.23 V vs. RHE and moves the onset potential negatively by 387 mV compared to the bare BiVO 4 . Furthermore, the charge injection efficiency is substantially boosted to 49% at 1.23 V RHE , nearly 5 times as that of pure BiVO 4 . With detailed physical and electrochemical characterization, we reveal the essential reason for the boosted photoelectrochemical activity. Appropriate Mo doping can simultaneously enhance the carrier density and electron mobility of BiVO 4 . Specifically, more (0 4 0) facet are exposed for retarding charge recombination and increasing photocatalytic reaction sites. Then the simple SILAR process grows AgVO 3 nanoparticles homogeneously with uniform diameter of 3–5 nm on BiVO 4 , forming p-n heterojunction to accelerate charge separation, and abundant oxygen vacancy emerged on the surface, which has been demonstrated as active sites for water oxidation reaction.
危险品化学品经营许可证（带存储）