Effects of Co Addition on Microstructure Evolution and Efficient Hydrogen Evolution of Self-Supported Fe–P@Cu Immiscible Alloy

Abstract

In this article, the effects of Co addition on microstructure evolution and catalytic efficiency variation of an Fe–P@Cu immiscible alloy were systematically studied. According to the first-principles molecular dynamics simulations, it was found that P in the Fe–P@Cu alloy with Co addition would be preferentially bonded with Fe and/or Co in the first coordination shell, and Cu and (Fe+Co) atoms tended to appear on the opposite side of P atom in the three-dimensional cluster configuration, which would have a significant guiding effect on the subsequent solidification process. Through the microstructure analysis, it was observed that the addition of Co element had an inhibitory action on the liquid phase separation behavior due to the changes of interfacial tension, resulting in the formation of a fine second phase structure. Through the electrochemistry characteristics, it was found that the overpotentials of Fe–P@Cu metallic catalysts containing 8% Co and 16% Co with a current density of 10 mA/cm2 have been improved to be 160 and 155 mV in 0.5 M H2SO4 respectively. This excellent catalytic performance might be mainly attributed to the rapid transport of ions and the remarkable amount increase of electron transfer, resulting in the obvious promotion of the hydrogen evolution reaction of (FexCo1–x)nP@Cu alloys.