Fabricating highly active Pt atomically dispersed catalysts with the co-existence of Pt-O1Ni1 single atoms and Pt sub-nanoclusters for improved hydrogen evolution

Abstract

Atomically dispersed catalysts (ADCs), including single atoms and sub-nanoclusters, simultaneously, are considered as the most promising candidate to boost the reaction kinetics of hydrogen evolution reaction (HER). However, the correlation between the coordination environment of single atoms and catalytic activity has not been clearly discussed in ADCs system. Herein, Pt ADCs with the different coordination structures were fabricated by a facile sulfurate route coupling deposition strategy. Importantly, Pt ADCs, including Pt-O1Ni1 single atoms and Pt sub-nanoclusters (Pt1+n/Ni3S2), show good basic HER activity, which just need 17 mV at 10 mA cm−2. Meanwhile, the turnover frequency for Pt1+n/Ni3S2 is 0.49 H2 s−1 under the overpotential of 100 mV, which is 8.6 times higher than Pt/C. Besides, the assembled RuO2 || Pt1+n/Ni3S2 system could get 100 mA cm−2 current density under 1.7 V cell voltage in alkaline water electrolyzer. Notably, in-situ Raman and attenuated total reflection-surface enhanced infrared absorption spectroscopy reveal that Pt-O1Ni1 coordination is conducive to promoting the fracture of H-O-H bond, realizing the rapid transform of Pt-H* intermediates. Further, density functional theory calculations confirm Pt single atoms with Pt-O1Ni1 coordination environment in Pt1+n/Ni3S2 serves as the main role for HER because Pt-O1Ni1 are more likely to accelerate the production of Pt-H* at the Pt sites, extremely achieving the rapid HER progress. This work discloses the structure-activity relationship in ADCs system, which is essential for the development of highly active electrocatalysts.