WSe2 nanofilms grown on graphite as efficient electrodes for hydrogen evolution reactions

Inexpensive graphite substrate is applied to grow WSe 2 nanofilms for catalytic application in the hydrogen evolution reaction . W nanofilms with a thickness of about 10 nm were deposited onto the graphite substrate by direct-current magnetron sputtering . The graphite with 10 nm W nanofilms was rapidly selenized at 600 °C in horizontal tube furnace to form WSe 2 nanofilms. Scanning electron microscopy, Raman spectroscopy , high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy indicated that graphite surface was covered by nano-sized vertically aligned WSe 2 platelets. The effects of the N 2 pressure in the selenization process on the HER performance have been studied in details. Turning of the selenization parameters can optimize the HER performance of the WSe 2 nanofilms, which has been evaluated via linear sweep voltammetry and Tafel slope. WSe 2 nanofilms prepared at the highest N 2 pressure of 0.08 MPa behave optimal performance. The current density reaches 10 mA cm −2 at an over potential around −189 mV vs reversible hydrogen electrode and corresponding Tafel slopes is ∼72 mV dec −1 . WSe 2 nanofilms electrodes exhibit high stability in acidic solution which shows no degradation after 10000 continuous cycles. Thus, WSe 2 nanofilms exhibit superior electrocatalytic performance which is much better than those recently reported grown on carbon paper substrate and W foil.