Computational design of a switchable heterostructure electrocatalyst based on a two-dimensional ferroelectric In2Se3 material for the hydrogen evolution reaction

Abstract

A theoretical design for an ON–OFF switchable HER catalyst using the two-dimensional ferroelectric (2D-FE) III₂VI₃ compound In₂Se₃ is reported in this paper. With vertical stacking of the basal plane of In₂Se₃ on top of the transition metal cobalt, a set of ab initio calculations reveals that the reversible polarization switching of In₂Se₃ can turn the HER activity of the heterostructure ON and OFF. The principle of HER activation/deactivation of the heterostructure is discussed in terms of the electronic structures, and the polarization-dependent modulation of electronic energy and charge transfer between In₂Se₃ and the transition metal are identified as the key factors. The distinct electron transfer mechanisms for the structures based on mono- and bilayers of In₂Se₃ are identified in terms of the different electronic connections between Co and In₂Se₃, and the structures are labelled as “direct” and “indirect” catalysts, respectively. This work provides insight into a possible pathway for designing dynamically controlled electrocatalysts based on 2D materials without introducing any chemical disorder.