Anchoring single metal atoms has been demonstrated as an effective strategy to boost the catalytic performance of non-noble metal 1T-MoS2 towards hydrogen evolution reaction (HER). However, the dual active sites on 1T-MoS2 still remain a great challenge. Here, first-principles calculations were performed to systematically investigate the electrocatalytic HER activity of single and dual transition metal (TM) atoms bound to the 1T-MoS2 monolayer (TM@1T-MoS2). The resulted Ti@1T-MoS2 exhibits excellent structural stability, near-thermoneutral adsorption of H* and ultralow reaction barrier (0.15 eV). It is a promising single metal atom catalyst for HER, outperformed the reported Co, Ni and Pd anchoring species. Surprisingly, by further introducing Pd atoms coordinated with S atoms or S vacancies on the Ti@1T-MoS2 surface, the resulted catalyst not only maintains the high HER activity of Ti sites, but also achieves new dual active moiety due to the appropriate H* adsorption free energy on Pd sites. This work is of great significance for realizing dual active centers on 1T-MoS2 nanosheets and offers new thought for developing high-performance electrocatalysts for HER.
Keywords: 1T-MoS2 monolayer; dual active centers; hydrogen evolution activity; reaction mechanism; single metal atom catalysts.