Prompt Hole Extraction Suppresses V<sup>5+</sup> Dissolution and Sustains Large-Area BiVO<sub>4</sub> Photoanodes for Over 2100 h Water Oxidation
Renbo Lei, Yupu Tang, Weitao Qiu, Shihan Yan, Xu Tian, Qian Wang, Qindong Chen, Zhenhui Wang, Wei Qian, Qiyong Xu, Shihe Yang, Xinwei Wang
Abstract
Nanostructured bismuth vanadate (BiVO 4 ) is at the forefront of emerging photoanodes in photoelectrochemical tandem devices for solar water splitting owing to the suitable band edge position and efficient charge separation capability. However, the (photo)chemical corrosion involving V 5+ dissolution limits the long-term stability of BiVO 4 . Herein, guided by DFT calculations, we introduce an ALD-derived NiO x catalyst layer on BiVO 4 to stabilize the surface Bi–O bonds, facilitate hole extraction, and thus suppress the V 5+ dissolution. At the same time, the ALD NiO x catalyst layer could efficiently suppress the surface recombination and accelerate the surface OER kinetics, boosting the half-cell applied bias photon-to-current efficiency of BiVO 4 to 2.05%, as well as a fill factor of 47.1%. By adding trace NaVO 3 to the electrolyte, the NiO x /BiVO 4 photoanode with an illumination area of 10.5 cm 2 shows a record operational stability of more than 2100 h.