Integrated Heterogeneous Engineering with the Vacancy Defect of Porous CoP_v-Mo_xP_v Nanosheets for an Accelerated Hydrogen Evolution Reaction

Abstract

Electrochemical water splitting is a possible way of realizing sustainable and clean hydrogen production but is challenging, because a highly active and durable electrocatalyst is essential. In this work, we integrated heterogeneous engineering and vacancy defect strategies to design and fabricate a heterostructure electrocatalyst (CoP v -Mo x P v /CNT) with abundant phosphorus vacancies attached to carbon nanotubes (CNTs). The vacancy defects enabled the optimization of the electronic structure; thereby, the electron-rich low-valent metal sites enhanced the ability of nonmetallic P to capture proton H. Meanwhile, the heterogeneous interface between bimetallic phosphides and CNTs realized rapid electron transfer. In addition, the Co, Mo, and P active species in the electrocatalytic process exposed increased amounts of active sites featuring porous nanosheet structures, which facilitated the adsorption of reaction intermediates and thus enhanced the hydrogen evolution reaction performance. In particular, the optimized CoP v -Mo x P v /CNT catalyst possesses an overpotential of 138 mV at a current density of 10 mA cm −2 and long-term stability for 24 h. This work offers insights and possibilities for the engineering and exploration of transition metal-based electrocatalysts through combining multiple synergistic strategies.

Simultaneously Improving Energy Storage and Oxygen Evolution Reaction by Causing Regional Defects in MOF-on-MOF Derived Hollow Se-Doped CoP-Fe2P Heterojunctions

“…On the other hand, vacancy defects have also been proven to be an effective method for altering interfacial chemical properties and exposing active sites. , Qian et al combined heterostructure engineering and vacancy strategies to fabricate a CoP v -Mo x P v /CNT electrocatalyst enriched with P defects and indicated that P vacancies can promote reaction kinetics and generate more active sites, ultimately displaying an overpotential of only 138 mV at 10 mA cm –2 for HER in 0.5 M H 2 SO 4 . Li et al reported NiSe 2 /Co 3 Se 4 -CNTs with rich Se vacancies and found that the generation of Se vacancies enhances the material’s adsorption capacity for OH – and increases the density of states (DOS) at the Fermi level, thereby improving the conductivity and enabling rapid interfacial electron transfer .…”