Oxidation-Sulfidation Approach for Vertically Growing MoS2 Nanofilms Catalysts on Molybdenum Foils as Efficient HER Catalysts

Abstract

Molybdenum disulfide (MoS2) has emerged as a promising electrocatalyst for hydrogen evolution reaction (HER). However, the performance of the catalyst suffers from the scarce active sites and poor electrical conductivity. Here we grow vertical MoS2 films on Mo foils to achieve highly catalytic active sites and enhanced electrical conductivity for facilitating high efficient HER catalysis. The ultrathin nanofilm with a thickness of around 4 nm on molybdenum foils is grown by a two-step method: (1) the molybdenum oxide (MoO2) nanofilm is achieved by oxidizing the surface of the Mo foil under a low pressure condition and (2) a MoS2 nanofilm is obtained by sulfurizing the MoO2 nanofilm in sulfur vapor at 700 °C within 1 min. Furthermore, the vertically aligned MoS2 nanofilm on Mo foils exhibit excellent stability in acidic solution and the electrochemical measurements show an onset overpotential of as low as 18 mV and a small Tafel slope of 55 mV/dec. The excellent HER catalysis originates from the synergisti...