Ag improves the performance of the oxygen evolution reaction by lowering the D-band center of the active site Ni

Abstract

The development of high activity catalysts with excellent durability is a great challenge to realize the industrialization of electrolytic water oxygen evolution. In this work, Ag nanoparticles modified cross column nickel-iron hydroxyl oxide system (NiFeAg) nanocomposites were synthesized by a two-step strategy. Through XPS spectrum, Tafel slope, and EIS electrochemical impedance spectroscopy, it was found that Ag mainly plays a conductive role, accelerates charge transfer, and adjusts the surface electronic structure, to improve the activity of the catalyst. Impressive is the overall hydrolysis performance, with a current density of 10 mA cm−2 achieved at an overpotential of 211 mV, which shows better performance than other catalysts reported in the literature. Finally, through the theoretical calculation of the determination steps of adsorption energy and rate of oxygen-containing intermediates, it is determined that the active center of the catalyst is mainly Ni site. According to the theory of D-band center, Ag can effectively adjust the D-band center, thereby adjusting the adsorption strength of Ni sites on the surface of NiFe catalyst to adsorbent, and finally improving the OER performance of the catalyst.