Robust carbon-encapsulated Ni nanoparticles as high-performance electrocatalysts for the hydrogen evolution reaction in highly acidic media

The major challenges related to non-noble-metal electrocatalysts toward the hydrogen evolution reaction (HER) in an acidic environment are to overcome their low efficiency and poor stability. For this purpose, we propose a rational top-down method to construct a hybrid structure of nickel encased by a carbon shell (Ni@C) using CH4 as a carbon source and Ni wire as a sacrificing template during an electrical explosion of wire. The Ni@C nanoparticles are introduced as highly active and durable non-noble metal electrocatalysts for the HER. The optimized Ni@C (15%) core-shell catalyst (CH4/Ar = 15/85 pressure ratio) demonstrates the highest catalytic activity for the HER with an overpotential of 85 mV to drive a current density of -10 mA cm(-2) and displays a low Tafel slope of 44 mV dec(-1). Another virtue of Ni@C (15%) is its superior stability during an unattenuated HER chronoamperometry for over 24 h. Furthermore, it endures over 168 h submerging in 2 M H2SO4 solution without losing its catalytic activity for HER. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

A rational top-down method was proposed to construct a hybrid structure of nickel encased by a carbon shell (Ni@C) as highly active and durable non-noble metal electrocatalysts for the hydrogen evolution reaction (HER) in an acidic environment. The optimized Ni@C (15%) core-shell catalyst demonstrated the highest catalytic activity with an overpotential of 85 mV and a low Tafel slope of 44 mV dec(-1). Ni@C (15%) also showed superior stability during continuous HER chronoamperometry for over 24 hours and remained active after being submerged in 2 M H2SO4 solution for 168 hours.