Mass transfer plays an important role in controlling the surface coverage of reactants and the kinetics of surface reactions, thus significantly adjusting the catalytic performance. Herein, we reported that H 2 O diffusion was modulated by controlling the thicknesses of the carbon black (CB) layer between the gas diffusion electrode (GDE) of Cu and the electrolyte. As a consequence, the product distribution over the GDE of Cu was effectively regulated during CO 2 electroreduction. Interestingly, a volcano-type relationship between the thickness of the CB layer and the faradaic efficiency (FE) for multicarbon (C 2+ ) products was observed over the GDE of Cu. Especially, when the applied total current density was set as 800 mA cm −2 , the FE for the C 2+ products over the GDE of Cu coated by a CB layer with a thickness of 6.6 μm reached 63.2%, which was 2.8 times higher than that (16.8%) over the GDE of Cu without a CB layer.

The interfacial structure of heterogeneous catalysts determines the reaction rate by adjusting the adsorption behavior of reaction intermediates. Unfortunately, the catalytic performance of conventionally static active sites has always been limited by the adsorbate linear scaling relationship. Herein, we develop a triazole-modified Ag crystal (Ag crystal–triazole) with dynamic and reversible interfacial structures to break such a relationship for boosting the catalytic activity of CO2 electroreduction into CO. On the basis of surface science measurements and theoretical calculations, we demonstrated the dynamic transformation between adsorbed triazole and adsorbed triazolyl on the Ag(111) facet induced by metal–ligand conjugation. During CO2 electroreduction, Ag crystal–triazole with the dynamically reversible transformation of ligands exhibited a faradic efficiency for CO of 98% with a partial current density for CO as high as −802.5 mA cm–2. The dynamic metal–ligand coordination not only reduced the activation barriers of CO2 protonation but also switched the rate-determining step from CO2 protonation to the breakage of C–OH in the adsorbed COOH intermediate. This work provided an atomic-level insight into the interfacial engineering of the heterogeneous catalysts toward highly efficient CO2 electroreduction.

Electroreduction of CO2 to HCOO− can be considered as the most economically valuable process. Herein, we developed lysine‐functionalized SnO2 nanoparticles (SnO2‐lys) as an efficient catalyst for the electroreduction of CO2 into HCOO−. During CO2 electroreduction, SnO2‐lys achieved a Faradaic efficiency for HCOO− of higher than 80% over a wide range of applied potentials from −0.5 V to −2.3 V versus reversible hydrogen electrode (vs. RHE). Notably, the partial current density for HCOO− reached as high as −351.9 mA cm−2 at −2.3 V vs. RHE. On account of kinetic analysis and mechanistic study, lysine‐functionalized SnO2 facilitated faradaic process and accelerated reaction kinetics via enhancing the CO2 activation, thus promoting the catalytic performance of the electroreduction of CO2 into HCOO−.