Search

The engineering of a heterojunction using various transition metal chalcogenides (TMCs) is a promising technique to boost electrochemical activity in the hydrogen evolution reaction (HER) process. Owing to the high price and low availability of noble metals, it is essential to develop a noble metal-free electrocatalyst at a low price with high activity and stability for sustainable hydrogen production. Herein, we synthesized CoS@NiS nanoparticles (NPs) using the hydrothermal method. All the synthesized materials were characterized thoroughly using XRD, XPS, and HRTEM. The XRD and XPS spectra confirm the formation of CoS@NiS heterostructure, and HRTEM images confirm the formation of CoS@NiS NPs. Further, synthesized CoS@NiS NPs demonstrated admirable HER performance with a low overpotential of 163 mV and a Tafel slope of 80.4 mV dec−1. Further, the EIS, C dl , ECSA and TOF results demonstrate that the formation of heterojunction between CoS and NiS could synergistically boost the charge transfer and promote the edge sites, which would enhance the HER activity. Also, CoS@NiS NPs demonstrated excellent stability for the continuous 15 h of the electrolysis process. An optimized doping by hydrothermal approach could modulate the crystal structure of CoS@NiS nanoparticles to improve the active sites, which can efficiently catalyze hydrogen evolution. [Display omitted] • CoS@NiS heterostructure was synthesized via hydrothermal method for electrochemical HER. • CoS@NiS was characterized thoroughly by XRD, XPS and HRTEM, and confirmed the formation of heterojunction. • A low overpotential and Tafel slope of 163 mV and 80.4 mV dec−1 were obtained towards HER using CoS@NiS NPs. • CoS@NiS demonstrated excellent stability for 15 h in 0.5 M H 2 SO 4 at 10 mA cm−2. [ABSTRACT FROM AUTHOR]