Co-deposition of nanocrystalline Co–Mo catalysts with a new fluffy microstructure for hydrogen evolution reaction based on N, N-dimethylformamide and ethylene glycol system

The co-deposition behavior of Co(II) and Mo(VI) in N,N-dimethylformamide and ethylene glycol system is observed. The result implies that Co–Mo co-deposition is typical induced deposition, while containing ordinary deposition process . Mo(VI) species in the system can suppress the reduction of Co(II) and its effect can be improved as the increase of Mo(VI) concentration, however, Co(II) species can promote the reduction of Mo(VI) and the effect can also be improved as the increase of Co(II) concentration. SEM micrographs indicate that all these films exhibit a fibrous surface morphology with a new fluffy microstructure. XRD pattern reveals that the Co–Mo film is a Mo solid solution in Co and its average size of crystalline grain is 9.5 nm. In addition, the electrocatalytic activity for hydrogen evolution reaction (HER) on these Co–Mo films is investigated. These results indicate that its electrocatalytic activity can be improved as Mo content increases from 1.02 to 2.84 wt% and the prepared Co–Mo film with 2.84 wt% Mo presents a high electrocatalytic activity and stability for HER with an overpotential of 81 mV at 10 mA cm −2 .