Interfacial electronic engineering of a Ni3ZnC0.7/Ni heterostructure embedded in N-doped carbon nanotubes for efficient alkaline electrocatalytic hydrogen evolution

Abstract

Bimetallic carbide electrocatalysts have great potential to outperform well-defined single metal ones for the electrochemical hydrogen evolution reaction (HER). However, the lack of regulation tactics of electronic structures largely impedes the upgrading of bimetallic carbides for efficient hydrogen evolution. Herein, a novel Ni₃ZnC_0.7/Ni heterostructure embedded in N-doped carbon nanotubes (Ni₃ZnC_0.7/Ni@CNTs) was synthesized by a facile one-step pyrolysis protocol. Experimental and theoretical results demonstrated that the electronic coupling interaction between Ni and Ni₃ZnC_0.7 triggered the redistribution of interfacial charge and optimized the electronic state density of metallic Ni sites, which reduced the H* adsorption–desorption energy barrier and thus accelerated the HER kinetics in the electrocatalytic process. The resulting Ni₃ZnC_0.7/Ni@CNTs required ultralow overpotentials of 93 and 256 mV to deliver current densities of 10 and 100 mA cm⁻² for the HER, respectively, and exhibited extraordinary long-term durability for at least 400 h in 1.0 M KOH solution. This work provides a novel perspective for the design of high-performance bimetallic carbide electrocatalysts for water splitting.