Engineering Charge Redistribution within Perovskite Oxides for Synergistically Enhanced Overall Water Splitting
Xixi Wang, Jie Dai, Chuan Zhou, Daqin Guan, Xinhao Wu, Wei Zhou, Zongping Shao
Abstract
Inexpensive, highly active, durable bifunctional catalysts for both the hydrogen and oxygen evolution reaction (HER and OER) are fundamental for efficient energy conversion. It has been reported that a favorable electronic structure and high electrical conductivity contribute to obtaining superior electrocatalytic activity for perovskites; thus, effective strategies for engineering abundant beneficial factors must be explored to enhance HER and OER. Hence, we report a novel two-step solid-state phase reaction method combined with bulk doping for constructing perovskite LaxSr1–xFe1–20yCo19yPyO3−δ-ab (LSFCP-ab) with modest B–O length and high electrical conductivity. Induced by the strong charge redistribution via Fe4+-O2–x-Co3+, abundant active sites (O22–/O–, Fe4+, Co3+/Co4+), moderate adsorption and desorption energies of the intermediates are obtained during OER and HER. Besides, the activated surface lattice oxygen O2-x could participate in the OER with lattice oxygen-mediated mechanism (LOM). Consequently, the optimal LSFCP-55 exhibits improved intrinsic OER and HER activity than that of La0.2Sr0.8FeO3-δ (LSF). Furthermore, the cell possesses a small cell voltage of 1.57 V with superior durability when it employed as the bifunctional catalyst in overall water splitting. This work provides a novel strategy to engineer beneficial electronic structures over perovskite oxides for sustainable energy conversion.