Modulation rate on adsorption and catalysis of 2D Pt: the effects of adsorbate-induced surface stress

Abstract

Recently, it has been reported for ultrathin 2D metals that positive surface stress of a clean surface (τ₁) can induce considerable compressive lattice strain towards optimized adsorption energy and catalytic properties (L. Wang et al., Science, 2019, 363, 870). We report negative surface stress (τ₂) induced by adsorbates at finite coverage counteracting the effects of τ₁, by studying the hydrogen adsorption properties and hydrogen evolution reaction (HER) catalysis performance of 2D Pt. Due to the competition between τ₁ and τ₂, the resultant lattice strain of 2D Pt is small. Consequently, modulation speed in adsorption energy and Tafel reaction barriers is significantly reduced as the Pt slab thickness decreases. Our study highlights the importance of properly including the effects of τ₂ in predicting and understanding the catalytic properties of 2D metals when coverage of adsorbates is high.