Selective-etching of MOF toward hierarchical porous Mo-doped CoP/N-doped carbon nanosheet arrays for efficient hydrogen evolution at all pH values

Abstract

CoP is demonstrated to be efficient for hydrogen evolution reaction (HER), but it suffers from unfavorable electronic and geometric structures to meet the requirement for future hydrogen economy. In this work, hierarchically porous N-doped carbon incorporated Mo-doped CoP nanosheet arrays are homogeneously grown on titanium foils (denoted as Mo-CoP/NC/TF) using a metal–organic-framework (MOF)-etching strategy. DFT simulations manifest that Mo dopants and N-doped carbon incorporation can synergistically modify the electronic structure of CoP, bringing optimal hydrogen adsorption free energies and accelerated interfacial charge transfer. Moreover, hierarchical nanoarray architectures can generate abundant accessible active sites, facile ion-diffusion path, and open-channels for gas release. Benefiting from these electronic and geometric advantages, the Mo-CoP/NC/TF electrocatalysts display superior activity and outstanding stability for pH-universal HER, requiring overpotentials of 59, 130, and 78 mV to drive a current density of 10 mA cm−2 in acidic, neutral, and alkaline electrolytes, respectively, which rivals most of the state-of-the-art non-precious electrocatalysts. This work may inspire the design and exploration of highly active and durable electrocatalysts by synergistically tailoring electronic and geometric structures toward hydrogen evolution.