Ultra-efficient post-treatment flame method to introduce abundant oxygen vacancies in BiVO4 photoanode toward solar water splitting

Oxygen vacancies (OVs) are widely introduced into metal oxide photocatalysts to improve their light absorption, carrier mobility, and surface reaction. It is still challenging to use typical OV generation strategies for achieving high efficiency, low cost, and good controllability. Here, we develop the control-lable and ultra-efficient post-processing flame method to introduce rich OVs into monoclinic BiVO4 pho-toanode in 20 s. The experiment parameters including the fuel-to-oxygen equivalence, distance, and annealing time were governed to adjust the electronic structure and PEC performances of the resultant BiVO4 photoanodes. As a result, the photocurrent density was enhanced up to 3.14-fold, and a high photocurrent density of 3.07 mA cm(-2) was achieved. The introduction of OVs improves the carrier transport, adsorption, and activation of OH- ions, confirmed by experimental and computational results. Furthermore, the presented flame strategy exhibited great versatility in the configuration of OV-enhanced metal oxide photoanodes such as Fe2O3, WO3, and TiO2. (C) 2022 Published by Elsevier Ltd.

Automated summary

In this study, a controllable and highly efficient post-processing flame method was developed to introduce oxygen vacancies into metal oxide photocatalysts, thereby improving their photoelectrochemical performance. By adjusting the experimental parameters, the electronic structure and photocurrent density of the BiVO4 photoanode were successfully controlled, and the positive effects of oxygen vacancies on carrier transport and activation of OH- ions were confirmed. Furthermore, the flame strategy exhibited versatility in the construction of OV-enhanced metal oxide photoanodes.