Nodal chain semimetal Co2MnGa: A magnetic catalyst with topological significance

Topological catalysis has become a major topic in electrochemical catalysis due to its outstanding performance in electrochemical reactions. Recently, a universal catalytic descriptor, known as topological surface states (TSS), has been proposed to describe catalytic performance in several nonmagnetic topological catalysts [Mater. Today 67, 23 (2023)]. However, the universality of this descriptor still lacks experimental evidence and has not been verified in magnetic topological catalysts yet. In this study, we investigate the catalytic performance and topological properties of the magnetic material Co2MnGa, which is a representative topological nodal chain semimetal with both theoretical and experimental validation. Our experimental findings demonstrate that Co2MnGa exhibits excellent catalytic performance in the hydrogen evolution reaction (HER). Our research reveals the presence of TSS from the nodal chain state is responsible for the high catalytic activity in Co2MnGa. Further, a direct relationship between the strength of TSS and Gibbs free energy can be built in the system. This comprehensive study has expanded our understanding of topological catalysts by exploring their material properties and corresponding topological mechanisms, extending our knowledge from nonmagnetic to magnetic categories.