Enhanced photoelectrochemical performance in BiFeO3/g-C3N4 p–n heterojunction photocathodes with ferroelectric polarization

Abstract

Ferroelectric has been considered as a promising material in the photoelectrochemical (PEC) water splitting area. Here, we design the hybrid ferroelectric–semiconductor heterostructure photocathode for enhanced PEC performance; BiFeO3 (BFO) is used for ferroelectric while two dimensional material g-C3N4 for the semiconductor. The optimized BFO/g-C3N4 heterojunction photocathode shows a 2.4 times enhancement in the photocurrent density than the pristine BFO sample. The improvement in the PEC performance is ascribed to the type II heterojunction formed between BFO and g-C3N4, resulting in the enhanced separation of the photogenerated charge carriers. More importantly, the PEC performance can be further improved by positive polarization of the BFO/g-C3N4 heterojunction photocathode. Our ferroelectric–semiconductor heterojunction material may be a promising solution for achieving highly efficient PEC systems.