Thermodynamic Miscibility-Guided Engineering of Bismuth-Tin Janus Catalysts for Durable Electrocatalytic CO₂...

Interfaces in heterogeneous bimetallic catalysts play a pivotal role in providing rich active sites and accelerating charge transfer during reaction process. However, designing an interface-rich catalyst with sufficient exposed active sites is crucial yet challenging. Janus catalysts containing bifunctional surfaces segregated by interfaces can boost the performance of electrochemical CO₂ reduction by optimizing electronic structure and reaction pathway. Herein, we construct a nano-sized Janus Bi-Sn catalyst by in situ electroreduction method, and the optimized structure and composition endow Bi-Sn catalyst with high FE_HCOO- of 95.5% (-0.9 V) and remarkable structural stability (310 h) in H-type cell. The ab initio molecular dynamics (AIMD) simulation validates that the good thermodynamic miscibility between Bi and Sn favors the decrease of atomic segregation rate during ambient electroreduction process facilitating the formation of interfaces. Theoretical and experimental results reveal that Bi-Sn interface pattern demonstrates moderate electronic interaction facilitating the decrease of adsorption free energy of HCOO* by optimizing the p-orbital energy level of Sn. Moreover, Janus Cu-Sn and Cu-Co catalysts were fabricated via in situ electroreduction strategy verifying the universality of the proposed method. This work provides new sights into engineering nonprecious Janus structured catalysts based on in situ electroreduction strategy.