Unique three dimensional architecture using a metal free semiconductor cross linked bismuth vanadate for efficient photoelectrochemical water oxidation
Abstract In this study, we report a unique design of nano porous bismuth vanadate (BiVO 4 photoelectrode decorated with graphene linked carbon nitride (GCN) nanosheets and their potential application in solar driven photoelectrochemical water oxidation. Especially, an integrated sandwich like heterojunction with highly interconnected porous structure, comprising two dimensional GCN sheets and three dimensional BiVO 4 was successfully synthesized with significantly enhanced photoelectrochemical activity. The prepared photoelectrode achieves up to 1.98 mA cm 2 (1.23 V vs RHE) under AM 1.5G solar light irradiation, 2.06 times compared with pristine BiVO 4 (0.96 mA cm 2 at 1.23 V vs RHE) After deposition of cobalt phosphate nanoparticles as water oxidation electrocatalyst, a plateau photocurrent of 3.42 mA cm 2 (1.23 V vs RHE) with a maximum photo conversion efficiency of 1.28% was achieved on the prepared photoanode. The highly improved photoelectrochemical performance can be attributed to suitable band matching facilitating efficient charge separation between GCN and BiVO 4 as well as the desirable incorporation of rational designed dimensionality dependent heterojunction for promoted solar energy utilization. More importantly, the combined experimental results and computational simulations reveal that the strong donor acceptor coupling between GCN sheets and porous BiVO 4 facilitates the separation and transfer of photoinduced electron hole pairs, accounting for the highly promoted photoelectrochemical performance.