Improvement of SnFe2O4 OER electrochemical property by Sm doping for water splitting

Abstract

Electrocatalysts are crucial for achieving highly efficient renewable energy conversion and storage applications. Nevertheless, doping proves to be a successful approach in creating affordable spinel oxides that exhibit exceptional electrochemical capabilities. Our study focuses on the preparation of a samarium (Sm)-doped SnFe2O4 catalyst to expand the activity and stability of the oxygen evolution reaction (OER). However, the Sm-doped SnFe2O4 catalyst shows a highly encouraging overpotential of 179 mV at a current density of 10 mA cm−2 and a reduced Tafel slope of 32 mA dec−1. It maintains its durability for a duration of 40 h and even after undergoing 5000th cycles. The Sm-doped SnFe2O4 catalyst exhibits several positive effects, including reduced overpotential, higher catalytic current density, improved charge transfer kinetics (Rct = 0.29 Ω), and increased ECSA (111.62 cm2) value. These improved superior activity of Sm-doped SnFe2O4 catalyst can be attributed to factors such as its unique interconnected structures morphology, strong synergistic effects of Sm with Sn and Fe and the robust OH− adsorption, which are more pronounced compared to the un-doped SnFe2O4, which greatly enhanced their performance in OER activity. These findings indicate that by incorporating rare earth (Sm) dopant with a high valence state, spinel oxide can be fine-tuned to potentially enhance OER optimization for energy-producing applications.