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. MoSe2 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 MoSe2 nanoplatelets on the urchin-like HER-active conductive CoSe2 nanowire array. Nanostructured MoSe2/CoSe2 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 (MoSe2, MoSe2–CoSe2 hybrids, and so on). The abundant exposed active sites of MoSe2, as well as an efficient electrical contact between MoSe2 nanosheets and CoSe2 nanowires, which is beneficial for the outstanding HER performance of MoSe2/CoSe2 hybrid electrode.