Boosting Electrocatalytic HER Activity of 3D Interconnected CoSP via Metal Doping: Active and Stable Electrocatalysts for pH-Universal Hydrogen Generation

Abstract

© 2020 American Chemical Society. All rights reserved.Recently, many research studies have been focused on anion or cation substitution into the lattice of pyrite-type cobalt disulfide (CoS2) for enhancing the hydrogen evolution reaction (HER) performance. Nonetheless, finding the correct pair of anion-cation dual substitution with added synergistic effect for boosting pH-universal HER activity remains an ongoing challenge. Additionally, a generalized activity descriptor and the HER mechanism in alkaline media remain elusive. Herein, to elucidate the HER mechanism and obtain the suitable anion-cation pair, we investigated the codoping of metal cations (Ti/V/Cr/Mn/Fe) and phosphorus anions into the CoS2 moiety. Our theoretical prediction revealed that Ti and P codoping into CoS2 exhibits superior HER performance at both pH 0 and 14, which is ascribed to the weak hydrogen binding energy in acid and fast water dissociation kinetics in alkaline media, thereby promoting HER. Remarkably, a follow-up experiment confirmed that Ti-CoSP showed astonishing HER activity inducing low overpotentials of 44 and 132 mV at -10 mA cm-2 in acidic and alkaline media, respectively, with superior stability for 40 h