Tunable hydrogen production of a transition metal-anchored CuInP2S6 monolayer with a ferroelectric switch

Abstract

The HER activity of a ferroelectric CuInP₂S₆ monolayer anchored by 3d transition metals was systematically investigated using first-principles calculations. The anchored 3d transition metals and ferroelectric switch could modulate the HER performance of CuInP₂S₆ monolayers. For example, the hydrogen adsorption free energy for Fe@CuInP₂S₆(↑) was 0.86 eV, while that of Fe@CuInP₂S₆(↓) fell to only 0.05 eV. The solar-to-hydrogen energy conversion efficiency of Cr@CuInP₂S₆(↓) and Fe@CuInP₂S₆(↓) were as high as 15.67% and 28.73%, respectively. Besides, a modified d band center model was proposed to predict the HER activity of the anchored CuInP₂S₆ monolayer.