Negatively Charging Nonprecious Metal Phosphides/Selenides via General Polyaniline Coating for Improved Alkaline H<sub>2</sub> Evolution
Zhiwei Zhu, Xiangxiong Chen, Jinlong Liu, Sanjun Fan, Bo You
Abstract
Nonprecious metal phosphides/selenides have been extensively investigated as competent electrocatalysts for the alkaline hydrogen evolution reaction (HER) toward H 2 production, although high overpotentials are still needed due to the sluggish kinetics of the alkaline HER associated with water dissociation. Herein, we present a universal approach to negatively charge Ni 5 P 4, NiSe x, and CoP x, via a one-step aniline electropolymerization coating, for an improved alkaline HER. Physicochemical characterizations and density functional theory (DFT) calculations reveal that the surface-coated polyaniline (PANi) renders underlying active species negatively charged due to strong electronic coupling, which leads to accelerated water dissociation via attractive interaction between electron-deficient hydrogen atoms and the repulsive interaction between electron-rich hydroxyl group. Accordingly, the resulting Ni 5 P 4 @PANi for instance exhibits exceptional alkaline HER performance with a significant 680 mA cm –2 at an overpotential of 300 mV, outperforming those of the Ni 5 P 4 counterpart (155 mA cm –2 ) and Pt/C (430 mA cm –2 ) under the same conditions.