Construction of bimetallic FeCo–SA/DABCO nanosheets by modulating the electronic structure for improved electrocatalytic oxygen evolution

Abstract

For energy conversion and storage, the electrochemical oxygen evolution process (OER) is the crucial half-reaction process. The amphiprotic characteristics of sulfamic acid are due to its amine and sulphonic acid functional groups. Metal-based catalysts can be utilized to fabricate bimetallic and dual-ligand linked FeCo–SA/DABCO nanosheets with improved catalytic performance. The crystal structure of bimetallic FeCo–SA/DABCO consisted of alternating organic hydrocarbons SA and DABCO and inorganic metal–oxygen layers. FeCo–SA/DABCO provided an overpotential (η₁₀) of 290 mV to achieve a current density of 10 mA cm⁻² together with a small Tafel slope of 112.79 mV dec⁻¹ and also exhibited long-term durability. Electrochemical results showed that FeCo–SA/DABCO was superior to FeCo–SA and Co–SA/DABCO. Density functional theory calculations indicated that the theoretical overpotential of FeCo–SA/DABCO is 0.62 eV, which was lower than that of FeCo–SA. The introduction of composite SA/DABCO ligands can change the rate-determining step, which can improve the conductivity and reduce the reaction barrier for the formation of intermediates, thereby affecting the catalytic activity and changing the overall electron transfer capacity.