Boosting carrier dynamics of BiVO_(4) photoanode via heterostructuring with ultrathin BiOI nanosheets for enhanced solar water splitting

摘要

Bismuth vanadate(BiVO_(4))has been one of the most promising candidates for solar water splitting while still suffers from poor bulk charge transport that limits its solar to hydrogen conversion efficiency.We demonstrate in this work an efficient strategy for boosting bulk charge transport of BiVO_(4) through the facile impregnation of as-prepared BiVO_(4) photoanode in the precursor solution of ultrathin BiOI nanosheets.Such impregnation creates increased oxygen vacancies in the bulk of BiVO_(4) through the reduction of V^(5+)to V^(4+)by I^(-),which greatly improves bulk separation efficiency for BiVO_(4)-BiOI up to 65.9%at 1.23 V_(RHE) from the original 51.9%of pure BiVO_(4).Moreover,the decoration of the BiOI nanosheets on BiVO_(4) photoanode is also beneficial for addressing the carrier dynamics at surface due to the matched energy levels of BiOI nanosheets and BiVO_(4).The introduced plenty of oxygen vacancies in the bulk of BiVO_(4) and the built-in electric field in BiVO_(4)-BiOI synergistically improve the photocurrent density at 1.23 V_(RHE) up to 3.88 mA cm^(-2).We believe that such facile impregnation strategy will pave an alternative way to the development of highly efficient BiVO_(4) photoanode.