Interfacial Heterojunction-Engineered Fe2O3/CoFe-Layered Double Hydroxide Catalyst for the Electrocatalytic Oxygen Evolution Reaction

Layered double hydroxide (LDH) materials have emerged as perspective anode catalysts for the electrocatalytic oxygen evolution reaction (OER) to substitute the high-price noble metal catalysts. However, the OER performance of LDH is unsatisfactory as a result of its limited electro-conductivity and sluggish surficial water oxidation kinetics. Here, we reported a Fe2O3/CoFe-LDH heterostructure electrocatalyst through a facile hydrothermal process. By in situ decorating CoFe-LDH with Fe2O3 nanospheres, a boosted electrocatalytic OER performance is evidenced from the Fe2O3/CoFe-LDH catalysts with an overpotential of 240 mV for the benchmarked current density and a Tafel slope of 70.3 mV dec(-1). As a result of the uniquely matched energy band alignments between Fe2O3 and CoFe-LDH, a Fe2O3/CoFe-LDH interfacial type-II heterojunction is evidenced. As such, the heterojunction-induced charge transfer driving force greatly enhances the charge transfer capability of Fe2O3/CoFe-LDH, thus improving the OER performance. This work offers a novel approach toward enhancing the electron transfer kinetics of general semiconductor-based catalysts by rational heterojunction engineering.