Hydrogen Evolution Using a Highly Efficient MoS2-Carbon Nano-Onion Heterostructure Electrocatalyst

Abstract

Hydrogen, a clean and sustainable energy source, can be produced by electrochemical water splitting using an electrocatalyst. However, developing an inexpensive, efficient catalyst for hydrogen evolution reaction (HER) is a challenge as it is difficult to obtain an electrocatalyst with a large accessible active surface. In this study, a sulfide of a non-noble metal, molybdenum, was employed as an electrocatalyst. Due to the restacking of 2D MoS2 layers, access to the active area was limited. This drawback of the 1T MoS2 catalyst was overcome by incorporating the carbon nano-onion (CNO). The unique MoS2-CNO heterostructure formed by growing a few-layered 2D 1T MoS2 on the CNO core facilitated smooth and barrier-free charge transfer through the heterojunction formation. This heterostructure mitigated restacking and maintained structural stability, providing a long-term high-performance catalyst. This MoS2-CNO exhibited an excellent HER performance with an overpotential of 53 mV vs. RHE and a Tafel slope of 40.8 mV dec-1 for over 25 h, showing it one of the best HER catalysts, next to platinum. This study highlights a new, highly stable, highly performing non-noble metal catalyst for electrochemical water splitting applications.