Prompt Hole Extraction Suppresses V5+Dissolution and Sustains Large-Area BiVO4Photoanodes for Over 2100 h Water Oxidation

Nanostructured bismuth vanadate (BiVO4) 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 V5+dissolution limits the long-term stability of BiVO4. Herein, guided by DFT calculations, we introduce an ALD-derived NiOxcatalyst layer on BiVO4to stabilize the surface Bi–O bonds, facilitate hole extraction, and thus suppress the V5+dissolution. At the same time, the ALD NiOxcatalyst layer could efficiently suppress the surface recombination and accelerate the surface OER kinetics, boosting the half-cell applied bias photon-to-current efficiency of BiVO4to 2.05%, as well as a fill factor of 47.1%. By adding trace NaVO3to the electrolyte, the NiOx/BiVO4photoanode with an illumination area of 10.5 cm2shows a record operational stability of more than 2100 h.