Effect of selenization parameters on hydrogen evolution reaction activity of WSe2 electrodes

WSe2 films were prepared on inexpensive graphite substrate through direct-current magnetron sputtering and rapid selenization for catalytic application in the hydrogen evolution reaction (HER). The effects of the temperature and time in selenization process on the HER activity were studied in details. Scanning electron microscopy and Raman spectroscopy indicates that the graphite surface is covered by WSe2 nanosheets. The HER activity of WSe2 samples prepared at different conditions has been evaluated via linear sweep voltammetry. Through adjusting selenization parameters, the WSe2 nanofilms consists of the proper nanosheets has been prepared with the optimal HER activity. It's important to control the number, the size and crystallinity of WSe2 nanosheets which take responsibility for the HER activity. WSe2 electrodes prepared at 500 °C for 10 min exhibit high stability in acidic solution and get the optimal activity with an over potential around −179 mV vs reversible hydrogen electrode (RHE) at the current density of 10 mA cm−2.