A nickel nanoparticle/carbon quantum dot hybrid as an efficient electrocatalyst for hydrogen evolution under alkaline conditions

Abstract

The exploration of an efficient electrocatalyst for hydrogen evolution reaction (HER) from water is a key to relieve the energy crisis, which is a great challenge. Herein, a nickel nanoparticle/carbon quantum dot (Ni/CQD) hybrid is synthesized and evaluated as an electrocatalyst for HER under a strongly alkaline medium (1 M KOH solution). The obtained Ni/CQD hybrid shows good catalytic ability for HER with an onset potential comparable to that of Pt wire and a low Tafel slope of 98 mV dec⁻¹, which may be attributed to the Ni–O–C interface between Ni NPs and CQDs. The Ni/CQDs also exhibit high stability after 1000 CV cycles with negligible current loss (around 1 mA cm⁻²). Moreover, the catalytic ability of Ni/CQDs can be further improved under visible light illumination, suggested by a lower Tafel slope of 77 mV dec⁻¹.