Heterointerface engineering constructs microenvironment enhancing catalytic kinetics of Fe/Ni oxyhydroxide@FeNi alloy for overall water splitting

Abstract

The design and preparation of efficient electrocatalysis to promote electrochemical water-splitting are vital for the hydrogen economy. Catalytic kinetics can be significantly enhanced by adjusting the structure and composition of non-noble metal electrocatalysts. Herein, we report efficient and low-cost FeNi alloys/oxyhydroxide nanostructure composites via one-step galvanostatic electrodeposition on cleaned SSM (stainless steel mesh). In a 1.0 M KOH solution, the as-prepared FeNi-(1 : 1) O_x(OH)_y can efficiently convert water to H₂ and O₂ with overpotentials of 325 and 347 mV, respectively, to achieve a current density of 100 mA cm⁻². The construction of an alkaline electrolytic cell by employing FeNi-(1 : 1) O_x(OH)_y as anode and cathode achieved an overall cell voltage of 1.897 V to attain 100 mA cm⁻² for 1.0 M KOH. Theoretical and experimental analyses indicate an FeNi alloys/oxyhydroxide heterostructure can be used to modulate the microenvironment on the surface to obtain the optimal microenvironment for HER and OER. Our strategy of heterointerface engineering to construct microenvironment-enhancing catalytic kinetics may create a promising pathway to develop the overall water-splitting performance of the binary metal alloy.