Self-Supportive Bimetallic Selenide Heteronanostructures as High-Efficiency Electro(pre)catalysts for Water Oxidation

Developing oxygen evolution reaction (OER) catalysts is intricate and challenging, involving a four-electron transport process coupled with conversion of O-H bonds into O-O bonds. This paper proposes a simple one-step synthetic strategy for preparing self-supported Cu₂Se/NiSe₂heteronanostructure electrodes for the OER with well-defined heterointerfaces by directly embedding onto the conductive nickel foam substrate. The prepared catalyst significantly enhances OER activity with low overpotentials of 277 and 290 mV at current densities of 50 and 100 mA cm^-2, respectively, which is attributed to electronic structure modulation by synergetic interactions and enhanced charge transportation between Cu₂Se and NiSe₂nanostructures. The as-prepared electrodes achieved high durability in 1 M KOH, retaining initial activity levels after 24 h continuous operation. We performed comprehensive spectroscopic and microscopic characterization before and after the OER to clarify active species and relate them to OER catalysis. Enhanced catalyst efficiency arises from integrating multicomponent electrocatalytic systems, which has been emphasized by the present findings.