Nanoarchitectonic Ni-doped edge dislocation defect-rich MoS2 boosting catalytic activity in electrochemical hydrogen production

Abstract

The world is moving towards a more sustainable future, and hydrogen is emerging as a key player in this transition. Hydrogen production through the use of electrocatalysts is becoming increasingly popular as a sustainable and efficient method. Herein, we report the monodisperse nickel (Ni) nanoparticles incorporated molybdenum disulfide (MoS2) (Ni/MoS2) electrocatalyst synthesized via a hydrothermal method, followed by an annealing process. It is found that the edge dislocations which are topological defects that occur when a crystal lattice has an extra plane of atoms. These defects can drastically affect the chemical properties and electronic structure of materials, which can improve their electrocatalytic performance. However, defect-rich electrocatalysts for hydrogen evolution reaction (HER) is becoming more popular nowadays. It is not yet clear how the active sites of the edge dislocations of MoS2 affect the catalytic properties of hydrogen evolution. The most promising electrocatalyst without precious metals is considered to be metallic MoS2 (1T phase), which exhibits Pt-like HER performance in alkaline media. One of the expected functions of MoS2 is to act as a conductive support with relatively large surface area for more catalytically active and highly dispersed Ni species. The 1T-MoS2 exhibits remarkable catalytic properties for HER due to the abundance of active sites connected by edge dislocations. Compared with pristine MoS2, the edge dislocation defect-rich Ni/MoS2 shows the outstanding HER activity, delivering a current density of 10 mA cm−2 at an overpotential of only 89 mV with a lower Tafel slope of 59 mV dec−1. Additionally, chronopotential analysis is performed at a constant current density of 10 mA cm−2 for 30 h with minimal loss in overpotential, which demonstrates an extremely potential and stable HER catalyst.