Transition metal doping activated basal-plane catalytic activity of two-dimensional 1T'-ReS for hydrogen evolution reaction: a first-principles calculation study.

The two-dimensional 1T' phase of ReS2 has a unique structure and its electronic properties are independent of its thickness. These features distinguish ReS2 from other two-dimensional transition metal dichalcogenides (TMDCs) used as catalysts in the hydrogen evolution reaction (HER) and suggest that it may be a suitable alternative catalyst to the expensive Pt most commonly in this reaction. Similar to traditional TMDCs, the catalytic activity of ReS2 is mainly contributed by the edge sites, whereas the basal plane, which accounts for a large percentage of the surface area, has poor catalytic activity. Activation of the basal plane of ReS2 would be an ideal strategy by which to boost its catalytic performance. We used density functional theory calculations to show that the catalytic activity of the ReS2 basal plane can be efficiently activated by doping with transition metal (TM) atoms such as Mo, Cr, Mn, Fe, Co, Pt, Au and Ag. Our results indicate that doping with a TM not only significantly reduces the hydrogen adsorption free energy (ΔGH*) of ReS2 by tuning the adsorption behavior of the H atom on the ReS2 surface, but can also expose more active sites by introducing more unsaturated electrons. Pt-doped ReS2 showed the highest catalytic activity for the HER of all the TM-doped ReS2 systems investigated, with ΔGH* = 0, a low reaction barrier and an increased density of active sites on the basal plane. More importantly, ReS2 doped with the non-noble TMs Mo and Cr showed excellent HER catalytic activities comparable with those of Pt-doped ReS2. Our findings will help to guide the future design of new HER catalysts based on TMDCs.