Hybrid Electrocatalysts of NiMo and Molybdenum Sulfide for Hydrogen Evolution Reaction

The best known catalysts for the hydrogen evolution reaction (HER) are platinum group precious metals, but the scarcity and high cost of these materials prohibit their wide-scale deployment. As a alternatives, nickel-based alloy (NiMo, NiW, NiFe etc.) catalysts show high electrocatalytic activity for HER, but they often degrade in acidic solutions. Recently, Molybdenum sulfides nanomaterials have drawn great attention due to their low cost, high chemical stability, and excellent photocatalytic and electrocatalytic properties in HERs. They are potentially useful if they can be tailored for the development of hydrogen energy devices. In order to enhance the efficiency of inorganic catalysts, many research efforts have been made toward the modification of material properties, the formation of composite catalysts, and the fabrication of the electrodes with nano-architecture. In this paper, we will show the hybrid electrocatalysts of NiMo nanoparticles and molybdenum sulfide thin films for HER, showing high activity and stability. The main purpose of this work is to draw the synergetic effect of NiMo's high activity and high electrical conductivity and molybdenum sulfide's high activity and high chemical stability. We synthesized NiMo nanoparticles and molybdenum sulfide thin films with various compositions. The electrodeposited molybdenum sulfide films had amorphous structure of MoSx and/or MoOSx. The electrochemical and spectroscopical analysis to understand the catalytic activity of hybrid catalysts will be discussed.