Charge pumping enabling Co–NC to outperform benchmark Pt catalyst for pH-universal hydrogen evolution reaction

Abstract

A transition metal (TM) coupled with the N-doped carbon (NC) nanocomposite has been regarded as an alternative electrocatalyst that shows Pt-comparable activity towards the hydrogen evolution reaction (HER), but so far no examples of these have outperformed Pt in acidic, alkaline and neutral media due to the insufficient tuning of the intrinsic catalytic activity. Herein, we report an interfacial engineered VN/Co–NC electrocatalyst that can achieve a current density of 10 mA cm⁻² at overpotentials of only 44, 22 and 163 mV in 1.0 M KOH, 0.5 M H₂SO₄ and 1.0 M PBS solutions, respectively, which are not only superior to previously reported TM–NC examples but also surpass the commercial Pt@C catalyst. More inspiringly, the highly catalytic activity could be maintained for more than 72 h over a wide pH range. Density functional theory computations and synchrotron-based X-ray absorption fine structure investigations reveal that the exceptional catalytic performance can be traced mainly to the well-defined VN/Co heterointerfaces which have a suitable lattice mismatch, allowing the electron depletion of Co–NC via the charge pumping effect of VN and thus the optimization of adsorption free energy for hydrogen-intermediates.