BiVO4 photoanode decorated with cobalt-manganese layered double hydroxides for enhanced photoelectrochemical water oxidation

Abstract

Bismuth vanadate (BiVO4) is being widely identified as a leading n-type semiconductor material for photoelectrochemical (PEC) water splitting. Nevertheless, achieving efficient PEC water oxidation process through BiVO4 photoanode still faces serious challenge such as severe electron-hole recombination. In this case, PEC activity of BiVO4 photoanode was enhanced by decoration of three-dimensional CoMn-layered double hydroxide (CoMn-LDH) nanoflakes on the BiVO4 surface via a facile electrodeposition process. It was suggested that CoMn-LDH played a synergistic effect on broadening internal light absorption, which accelerated injection of holes carrier to electrolyte and alleviated the electron-hole recombination, resulting in expediting faster PEC water oxidation reaction kinetics. Consequently, the photocurrent density of BiVO4/CoMn-LDH photoanode achieved 2.69 mA cm−2 at 1.23 VRHE, 2.45 times higher than the pristine BiVO4. What's more, 220 mV negative-shift took place on onset potential that was further decreased to 0.31 VRHE. The vastly enhanced PEC performance was also prioritized to those of Co and Mn single relatives. This work demonstrated that the synergistic BiVO4/CoMn-LDH as a capable candidate material, can be utilized for effective PEC water splitting.