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 .
Guangci Li,Yanpeng Li,Guannan Lin,Da Wang,Peng Guo,Xuebing Li,Keng H. Chung
Co-Mo sulfide catalysts with different particle size and structures were prepared in ethanol-water mixed solvent followed by a low-temperature sulfurization process, and were tested in dibenzothiophene hydrodesulfurization . The effects of the ethanol/water ratio on the particle size of precursors, active phase composition, active site number, morphology, and hydrodesulfurization activity of the final catalysts were investigated. The atomic ratio of Co/Mo and active phase morphology of catalysts closely relate to the dielectric constant of ethanol-water mixed solvent. Appropriate dielectric constant favors the formation of (Co)MoS 2 slabs with shorter length (∼ 5.0 nm) and higher stacking number (∼ 4.3 layers), resulting in more coordinatively unsaturated sites, especially in the corner sites. The catalytic activity not only depends on the active sites of CoMoS phase, but also on that of Co 9 S 8 and MoS 2 phases because of synergistic effect. For MoS 2 and CoMoS phases, the corner sites show higher direct desulfurization activity than the edge sites.