Tuning the hydrogen activation reactivity on topological insulator heterostructures

Abstract

The central challenge faced in hydrogen evolution reaction is the low reaction efficiency when using non-precious materials as potential new types of electrocatalysts. Here, we report an elegant synergistic effect of local bonding and topological surface states (TSSs) for optimally enhanced hydrogen evolution reaction by invoking topological insulator heterostructures purely composed of abundant elements. Using first-principles calculations within density functional theory, we demonstrate that the three-dimensional topological insulator of Bi2Se3 covered with a single layer of ZnSe can function as an ideal platform for maximal hydrogen evolution reaction with optimal hydrogen adsorption free energy. Such a highly desirable functionality is attributed to the TSSs of Bi2Se3 serving as an electron bath in enhancing the hydrogen adsorption strength, which would be too weak on top of the ZnSe overlayer without considering topological effects, but too strong upon increasing the ZnSe overlayer thickness. We also demonstrate precise tunability of the vertical location of the TSSs via the ZnSe overlayer thickness, which can be exploited for other functionalities of such topological insulator heterostructures. The present study provides an important linkage between the topological insulators as a new class of quantum matter and catalytic materials for clean energy.