Electrokinetic Analysis‐Driven Promotion of Electrocatalytic CO Reduction to n‐Propanol

Abstract The electrocatalytic carbon dioxide or carbon monoxide reduction reaction (CO₂RR or CORR) features a sustainable method for reducing carbon emissions and producing value‐added chemicals. However, the generation of C₃ products with higher energy density and market values, such as n‐propanol, remains highly challenging, which is attributed to the unclear formation mechanism of C₃₊ versus C₂ products. In this work, by the Tafel slope analysis, electrolyte pH correlation exploration, and the kinetic analysis of CO partial pressure fitting, it is identified that both n‐propanol and C₂ products share the same rate‐determining step, which is the coupling of two C₁ intermediates via the derivation of the Butler–Volmer equation. In addition, inspired by the mechanistic study, it is proposed that a high OH^─ concentration and a water‐limited environment are beneficial for promoting the subsequent *C₂–*C₁ coupling to n‐propanol. At 5.0 m [OH⁻], the partial current density of producing n‐propanol (j_n‐propanol) reached 45 mA cm⁻², which is 35 and 1.3 times higher than that at 0.01 m [OH⁻] and 1.0 m [OH⁻], respectively. This study provides a comprehensive kinetic analysis of n‐propanol production and suggests opportunities for designing new catalytic systems for promoting the C₃ production.