Hydrogen evolution reaction of metal di-chalcogenides: ZrS2, ZrSe2 and Janus ZrSSe

Transition metal di-chalcogenides with stoichiometry MX2 (M: Mo, V, W, Pt and X: S, Se) are considered as one of the non-precious and effective catalysts for the production of clean hydrogen energy via water-splitting mechanism. The major drawback of these materials is their inactive basal plane as compared to their edge sites. Recently, Janus MoSSe-a novel sandwiched structure has been synthesized and predicted theoretically to obtain increased catalytic activity by applying strain, external electric field and by creating vacancy. In this work, we have used state-of-the-art density functional theory with dispersion correction (DFT-D3) to study the catalytic activity for hydrogen evolution reaction (HER) of ZrS2, ZrSe2 and Janus ZrSSe. From our calculations, we conclude that among these three systems, the Janus ZrSSe (DG = 1:19 eV; Delta G : Gibbs free energy) is a good catalyst and can be utilized for HER at edge site. Janus ZrSSe shows enhanced catalytic activity at S-edge as compared to its basal plane and Se-edge site; whereas ZrSe2 shows good catalytic activity at Se-edge rather than at the basal plane. The ZrS2 shows good catalytic activity at S-edge. Further, we have doped Nb, Pt and W atoms in ZrS2, ZrSe2 and Janus ZrSSe to see their effect on catalytic activity of pristine compounds and found that the Nb-doped ZrSe2 shows good catalytic activity for HER and is best among all considered systems with DG = 0:63 eV followed by Pt-doped ZrS2. This study provides a theoretical basis for future application of ZrS2, ZrSe2 and Janus ZrSSe based catalysts for HER. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.