Unveiling the Interfacial Species Synergy in Promoting CO₂ Tandem Electrocatalysis in Near-Neutral Electrolyte

The interfacial species-built local environments on Cu surfaces impact the CO₂ electroreduction process significantly in producing value-added multicarbon (C₂₊) products. However, intricate interfacial dynamics leads to a challenge in understanding how these species affect the process. Herein, with ab initio molecular dynamics (AIMD) and finite element method (FEM) simulations, we reveal that the highly concentrated interfacial species, including the *CO, hydroxide, and K⁺, could synergistically promote the C-C coupling on the one-dimensional (1D) porous hollow structure regulated interfacial environment. The Cu-Ag tandem catalyst was then synthesized with the as-designed structure, exhibiting a high C₂₊ Faradaic efficiency of 76.0% with a partial current density of 380.0 mA cm^-2 in near-neutral electrolytes. Furthermore, in situ Raman spectra validate that the 1D porous structure regulates the concentration of interfacial CO intermediates and ions to increase *CO coverage, local pH value, and ionic field, promoting the CO₂-to-C₂₊ activity. These results provide insights into the design of practical ECR electrocatalysts by regulating interfacial species-induced local environments.