Details

Autor(en) / Beteiligte

• Bu, Yuyu
• Tian, Jing
• Chen, Zhiwei
• Zhang, Qiang
• Li, Weibing
• Tian, FengHui
• Ao, Jin‐Ping

Titel

Optimization of the Photo‐Electrochemical Performance of Mo‐Doped BiVO4 Photoanode by Controlling the Metal–Oxygen Bond State on (020) Facet

Ist Teil von

• Advanced materials interfaces, 2017-05, Vol.4 (10), p.n/a

Ort / Verlag

Weinheim: John Wiley & Sons, Inc

Erscheinungsjahr

2017

Quelle

Wiley Blackwell Single Titles

Beschreibungen/Notizen

• Oxygen vacancy on semiconductor has been usually considered as donor contributor which can improve the charge transfer capacity of the photoanode. However, oxygen vacancy has also been found to perform as recombination center for the photogenerated charges. Herein, electrochemical reduction method is employed to treat the surface of Mo‐doped BiVO4 (BiMoVO) photoanode. Experimental data indicate that when the reduction potential is located at −0.8 V (vs Ag/AgCl), quasioxygen vacancy is formed on the (020) facet (only BiO bonds crack), the electron mobility and photo‐electrochemical (PEC) current density of the BiMoVO photoanode are increased dramatically. However, with the reduction potential increasing to −1.2 V, oxygen vacancy is formed on the surface of (020) facet (both BiO and VO bonds crack simultaneously), the PEC current density is decreased obviously. Further density functional theory calculation data point out that a moderate level of reduction is a key factor for the adjustment of photoanode performance. Thus, these results demonstrate first that oxygen vacancy actually is not the positive factor to improve the PEC performance of a BiVO4 photoelectrode, but the quasioxygen vacancy forming on the surface of the active facet is. Oxygen vacancy on the surface of BiVO4 photoanode is a double‐edged sword for the photo‐electrochemical performance. It can increase the free charge density of BiVO4, but inducing the recombination of free photogenerated carriers. This article demonstrates that quasioxygen vacancy forming on the surface of the BiVO4 active facet is the true reason to improve the photo‐electrochemical performance of it.