The effect of varying solvents for MoS2 treatment on its catalytic efficiencies for HER and ORR

Abstract

MoS₂ has been investigated intensively in the field of catalysis for the hydrogen evolution reaction (HER) in particular. Much effort has been made by various research teams worldwide to look into the specific catalyst design such as nano-structuring, defect engineering or hybrid structures. But what evades us is the fundamental preparation method for the dispersion of powdered MoS₂. Individual research teams with their best practices might be subjective and not validated by extensive experimental results. In this report, we find that the overpotential for the catalysis of HER varies from 0.57 to 0.72 V (freshly prepared) when different dispersion media are used, such as acetonitrile, N,N-dimethylformamide, ethanol, methanol and water. In terms of oxygen reduction reaction (ORR) catalysis, less significant differences were found. With both HER and ORR pertinent to the fuel cell industry, this report would serve as an insight to readers when comparing the results of MoS₂ catalysis across the literature from different research groups when different solvents were used as the dispersion medium.