A novel 0D/2D/2D hetero-layered nitrogen-doped graphene/MoS2 architecture for catalytic hydrogen evolution reaction

Abstract

• A hybrid of Ni@N-Gr with exfoliated MoS 2 is reasonably designed and synthesized. • Ni@N-Gr/MoS 2 provides a stimulating insight to form non-precious metal doping onto layered 2D/2D hetero-assembly. • The hybrid has high electronic conductivity and rich exposed active sites. • Ni@N-Gr/MoS 2 exhibits superior and durable electrocatalytic performance in acidic medium. Two-dimensional (2D) layered molybdenum disulfide (MoS 2 ) has emerged as a promising Pt-substituting electrocatalyst for the hydrogen evolution reaction (HER) recently. Despite the ever-growing interest in these MoS 2 based-materials, their catalytic performance is still far from satisfactory due to the nature of the inactive basal plane and poor conductivity. This work presents a novel nickel@nitrogen‐doped graphene@MoS 2 (Ni@N-Gr/MoS 2 ) triad heterostructure for catalytic HER. The as-synthesized Ni@N-Gr/MoS 2 assembly exhibits high intrinsic HER activity with a low overpotential of 270 mV at 10 mA cm −2 , an onset overpotential of 60 mV, a small Tafel slope of 56 mV dec −1 , and robust stability in 0.5 M H 2 SO 4 . The notable activity of the Ni@N-Gr/MoS 2 composites is attributed to two main causes (i) presence of further catalytic active sites due to the incorporation of Ni@N-Gr in the basal plane of MoS 2 (ii) improvement of the conductivity due to nitrogen-doped Gr; where a fast electron transfer takes place from Ni@N-Gr core to MoS 2 during HER. Our novel-hybrid strategy is promising as an electrochemical platform in industrial hydrogen production and hence can stimulate further structural realizations to employ other metal species.