Hydrogen spillover in Pt/Ni(OH)2/Mo2TiC2Tx electrocatalyst improves pH-universal hydrogen evolution reaction

Abstract

Electrocatalytic hydrogen evolution reaction (HER) shows potential to transition from fossil fuels to green renewable energy. Designed for high efficiency and stability electrocatalyst in pH-universal electrolyte is of great significance but challenging. Herein, a novel electrocatalyst of two-dimensional (2D) Mo2TiC2Tx MXene supported Pt/Ni(OH)2 (denoted as Pt/Ni(OH)2/Mo2TiC2Tx) is reported by hydrogen spillover effect for efficient HER in the full-pH range. The operando electrochemical characterization reveals that the hydrogen spillover phenomenon interactions between multi-functional catalytic sites, e.g. Pt, Ni(OH)2 and Mo2TiC2Tx, are used to enhance HER performance and expedite HER kinetics. Moreover, theoretical calculation via density functional theory demonstrates the Pt/Ni(OH)2/Mo2TiC2Tx possess free energy of absorbed hydrogen close to zero (≈– 0.09 eV), which leads to optimal activity. As expected, the electrocatalyst necessitates the overpotential of 25, 33 and 36 mV at 10 mA cm−2 in acidic, alkaline, and neutral conditions, respectively, which are outperforming Pt/C. This work furtherly demonstrates a new way to design a powerful electrocatalyst for pH-universal HER based hydrogen spillover phenomenon.