One-step synthesis of Co-doped 1T-MoS2 nanosheets with efficient and stable HER activity in alkaline solutions

Abstract The metallic phase of molybdenum disulfide (1T-MoS2) shows great potential for hydrogen evolution reaction (HER) in acid solutions. However, few works have been reported to enhance the intrinsic catalytic activity of 1T-MoS2 in basic solutions, which is more applicable for water splitting in large-scale applications. Here, we report a hydrothermal process for synthesizing cobalt-doped 1T-MoS2 nanosheets. The cobalt-doped 1T-MoS2 exhibits an overpotential of 240 mV at 10 mA cm−2 in 1 M KOH aqueous solutions and a small Tafel slope of 68 mV dec−1, which is much better than that of the pristine 1T-MoS2 and even superior to other MoS2-based catalysts operated in acid solutions. Moreover, the cobalt-doped 1T-MoS2 nanosheets show high stability, and remain metallic phase after being reserved in water for one month. Calculations based on density functional theory reveal that Co doping does not transform the pristine 1T-MoS2 into its semiconducting counterpart. In addition, the reduction of energy barrier of the initial water dissociation step is responsible for the facilitated HER process.