Mutual-Activation between Doped Pt-Single-Atoms and Basal-Plane Sites in 1T-TaS₂ Nanosheets Networks for Highly Efficient Hydrogen Evolution.

Abstract

Doping single atoms (SAs) into catalytically active substrates offers the possibility for both SAs and substrates to co-participate in the catalytic reactions (e.g., hydrogen evolution (HER)) toward highly improved overall performance. Semiconducting transition-metal dichalcogenides (TMDCs), especially MoS₂, have been selected as active substrates; however, their restricted edge-active sites and insufficient electronic modulation of SAs limit their practical applications. Herein, we report the preparation of Pt-SAs doped 1T-TaS₂ nanosheets catalysts via chemical vapor deposition followed by electrochemical deposition. The vertically aligned 1T-TaS₂ nanosheet networks can afford abundant edge and basal-plane active sites, and the low electronegativity of Ta enables effective modulation of the electronic structure of doped Pt-SAs. Notably, the designed catalyst exhibits comparable overpotential (∼145 mV at 100 mA cm^-2) and Tafel slope (∼33.8 mV dec^-1) to commercial Pt/C, while demonstrating 40-times higher Pt mass activity (∼10.92 A mg^-1 at 50 mV). Further density functional theory calculations reveal a mutual-activation mechanism; i.e., the Pt-SAs activate the basal-plane sites of TaS₂ and vice versa, inducing a synergistic enhancement of the HER performance. This work hereby discusses the fundamental mechanisms of Pt-SAs and TMDCs co-catalytic systems and offers design principles of high-efficiency and cost-effective HER catalysts.