The practical utilization of the hydrogen evolution reaction
(HER)
necessitates the creation of electrocatalysts that are both efficient
and abundant in earth elements, capable of operating effectively within
a wide pH range. However, this objective continues to present itself
as an arduous obstacle. In this research, we propose the incorporation
of sulfur vacancies in a novel heterojunction formed by MoS2@CoS2, designed to exhibit remarkable catalytic performances.
This efficacy is attributed to the advantageous combination of the
low work function and space charge zone at the interface between MoS2 and CoS2 in the heterojunction. The MoS2@CoS2 heterojunction manifests outstanding hydrogen evolution
activity over an extensive pH range. Remarkably, achieving a current
density of 10 mA cm–2 in aqueous solutions 1.0 M
KOH, 0.5 M H2SO4, and 1.0 M phosphate-buffered
saline (PBS), respectively, requires only an overpotential of 48,
62, and 164 mV. The Tafel slopes for each case are 43, 32, and 62
mV dec–1, respectively. In this study, the synergistic
effect of MoS2 and CoS2 is conducive to electron
transfer, making the MoS2@CoS2 heterojunction
show excellent electrocatalytic performance. The synergistic effects
arising from the heterojunction and sulfur vacancy not only contribute
to the observed catalytic prowess but also provide a valuable model
and reference for the exploration of other efficient electrocatalysts.
This research marks a significant stride toward overcoming the challenges
associated with developing electrocatalysts for practical hydrogen
evolution applications.