Activation of electrocatalytic properties of a-C films by doping with MoSex clusters

Abstract

Nanocomposite a-C(Mo/MoSex) thin films containing amorphous carbon matrix a-C, nano-Mo and MoSex ≥2 clusters were obtained by pulsed laser co-deposition of carbon and MoSe2. The deposition was carried out at room temperature onto a graphite substrate. Atomic content of the MoSex≥2 phase did not exceed 25%. The use of a buffer gas at a pressure of 10 Pa allowed to obtain the maximum Se/Mo ratio in the films and to increase the concentration of sp2-hybridized C atoms for high conductivity realization. The formation of MoSex≥2 cluster inclusions was the essential factor for activation of hydrogen evolution reaction (HER) in 0.5 M H2SO4 aqueous solution. These clusters also promoted cathodic deposition of Pt nanoparticles on the surface of a-C(Mo/MoSex) in a H2SO4/KCl solution when a Pt anode was used as a source of Pt. Hybrid Pt/a-C(Mo/MoSex) thin-film coatings with a low Pt loading (~6 μg/cm2) exhibit excellent HER property, which noticeably exceeds that of relatively thick Pt coating prepared on a graphite substrate by pulsed laser deposition.