Efficient photocatalytic water splitting of BiFeO3–BaTiO3 as a perovskite based n-n heterojunction toward H2 evolution without using sacrificial agent
Leila Haroonabadi, Shahram Sharifnia
Abstract
Construction of heterostructure photocatalysts is an effective strategy to achieve charge separation and enhance photocatalytic activity . Herein, perovskite-based n-n heterostructure of BiFeO 3 –BaTiO 3 was prepared and applied for water splitting process with the aim of H 2 production. The slope of Mott-Schottky plots revealed that both BiFeO 3 and BaTiO 3 are n -type photocatalysts with flat band potentials of +0.67 and −0.03 eV, respectively. The flat band potential of BaTiO 3 meets the potential required for reducing H + to H 2 . However, the results of PL and EIS demonstrated the high recombination rate of charge carriers in pure BaTiO 3 . By introducing BiFeO 3 and construction of n-n heterostructures , the charge separation and mobility were promoted as a result of charge transfer process. Based on the Fermi level positions, difference of the work function between the two photocatalysts, and the radical scavenger experiments results, the direct Z -scheme charge transfer mechanism is suggested in BiFeO 3 –BaTiO 3 heterojunction. The best photocatalytic H 2 evolution under UV–vis irradiation and without using sacrificial agent was obtained to be 328 μmol g −1 h −1 by a heterostructure composed of 70 wt % BFO.