Shape-Controlled Hematite: An Efficient Photoanode for Photoelectrochemical Water Splitting

Abstract

Photoelectrochemical water splitting has gained considerable interest in the past few decades because of its potential for harvesting solar light for H2 production. For harvesting solar light, the design of a semiconductor photoelectrode is the critical parameter to control performance. In this regard, vertically aligned, interconnected 2D nanosheets of α-Fe2O3 show the most efficient activity for PEC water splitting as compared to other morphologies like thick sheets and nanorods as the former absorb more light, provide less path length for photon penetration, and a short minority carrier (hole) diffusion length. Compared to thick sheets and nanorods, the separation efficiency of Fe2O3 nanosheet is 7.3, which is higher than the structures as mentioned above, at 1.23 V vs RHE. To further legitimize the efficacy of α-Fe2O3 nanosheet vis-à-vis the thick sheets and nanorods, Mott–Schottky analysis is performed to calculate carrier densities of 8.68 × 1020, 8.68 × 1019, and 2.89 × 1020 cm–3.