Experimental Demonstration of Topological Catalysis for CO 2 Electroreduction.

The past decade has witnessed substantial progress in understanding nontrivial band topology and discovering exotic topological materials in condensed-matter physics. Recently, topological physics has been further extended to the chemistry discipline, leading to the emergence of topological catalysis. In principle, the topological effect is detectable in catalytic reactions, but no conclusive evidence has been reported yet. Herein, by precisely manipulating the topological surface state (TSS) of Bi 2 Se 3 nanosheets through thickness control and the application of a magnetic field, we provide direct experimental evidence to illustrate topological catalysis for CO 2 electroreduction. With and without the cooperation of TSS, CO 2 is mainly reduced into liquid fuels (HCOOH and H 2 C 2 O 4 ) and CO, exhibiting high (up to 90% at -1.1 V versus reversible hydrogen electrode) and low Faradaic efficiency (FE), respectively. Theoretically, the product and FE difference can be attributed to the TSS-regulated adsorption of key intermediates and the reduced barrier of the potential-determining step. Our work demonstrates the inherent correlation between band topology and electrocatalysis, paving a new avenue for designing high-performance catalysts.