Self-supported molybdenum selenide nanosheets grown on urchin-like cobalt selenide nanowires array for efficient hydrogen evolution

The development of a highly efficient hybrid catalyst is desirable for the water splitting to produce hydrogen . MoSe 2 is one of the low-cost candidates; however, its activity for hydrogen evolution reaction (HER) is still not satisfactory due to the low conductivity and poor electrical contact with the charge collection substrate. Herein, we provide a simple approach of synthesizing vertically aligned MoSe 2 nanoplatelets on the urchin-like HER-active conductive CoSe 2 nanowire array. Nanostructured MoSe 2 /CoSe 2 hybrid catalysts obtained a current density of 10 mA cm −2  at overpotentials of only 129 mV, with a small Tafel slope of 38.2 mV dec −1 , which is superior to those of most transition metal dichalcogenides (MoSe 2 , MoSe 2 –CoSe 2 hybrids, and so on). The abundant exposed active sites of MoSe 2 , as well as an efficient electrical contact between MoSe 2 nanosheets and CoSe 2 nanowires, which is beneficial for the outstanding HER performance of MoSe 2 /CoSe 2 hybrid electrode.