Serendipity for Topological Insulator as Multifunctional Electrocatalyst

The design for multifunctional two-dimensional (2D) materials is considered as one of the main strategies to expand its application. Here, we propose that the already-synthesized organometallic lattice (Ni3(CNH)12) concurrently hosts topological and catalytic properties. Using first-principles calculations combined with tight-binding (TB) model, we demonstrate that the 2D Ni3(CNH)12 intrinsically possesses multiple Dirac cones along with flat bands passing through the Dirac bands. Taking the spin-orbital coupling (SOC) into account, all the degenerate points open gaps, spawning abundant topologically nontrivial insulating phases characterized by a nonzero Z2 topological invariant and edge states. Furthermore, because of its special geometry and electronic states, the 2D lattice can serve as a bifunctional electrocatalytic activity for overall water splitting with low overpotentials. Our current results offer a viable approach for the discovery of 2D organometallic materials with multifunctional application in spintronics devices and catalysts from the emerging field of topological materials.