High-performance hydrogen evolution reaction catalysts based on three-dimensional single nodal loop semimetals ScX (X = Cd/Ag/Cu/Rh)

Abstract

Topological materials have garnered attention as promising catalysts in electrocatalytic processes. Recently, a universal descriptor for topological catalysis, known as topological surface states (TSSs), has been proposed. The relationship between TSSs and the catalytic performance of materials has been established. However, since materials can host different types of nontrivial band crossings, their catalytic performance may be influenced by various types of TSSs, making it challenging to study the influence of a specific type of TSS. In this study, we introduce ScCd, a semimetal with a single nodal loop, as a topological catalyst. We observe that its catalytic performance is solely linked to the presence of this single nodal loop. Specifically, the nodal loop contributes to the presence of drumhead surface states, which enhance the surface density of states and electron mobility. Consequently, ScCd exhibits a low Gibbs free energy (about 0.08 eV), resulting in high performance in the hydrogen evolution reaction (HER), comparable to the classical precious metal catalyst Pt. Moreover, we discover that the high performance of ScCd in the HER is solely associated with the TSSs of the nodal loop, despite the presence of two pairs of Weyl points in its electronic band structure. We establish a linear relationship between the TSSs and the performance of ScCd in the HER, demonstrating that TSSs can serve as descriptors for its catalytic performance. As a topological catalyst, the performance of ScCd remains robust against perturbations such as doping and strains. As long as the symmetry-protected nodal loop persists, its performance remains stable. Therefore, our work not only demonstrates the application of nodal loop semimetals in catalytic reactions but also provides a clear physical understanding of the relationship between topology and catalytic performance.