Selective Electroreduction of CO2 to n‐Propanol in Two‐Step Tandem Catalytic System

Abstract Electrocatalytic reduction of CO 2 (CO 2 RR) to high‐energy‐density C 3 fuels like n ‐propanol has been widely recognized as one of the core technologies for both renewable energy storage and carbon neutrality. Unfortunately, exceptional catalytic sites that are able to simultaneously implement efficient conversion to C 1 and C 2 products are difficult to design for single electrolyzers, leading to poor activity and selectivity toward n ‐propanol. Alternatively, electroreduction of CO (CORR) has shown good performance toward C 3 fuels, but the cost and safety of gas storage hinder its industrialization. Herein, a system consisting of two tandem electrolyzers for converting CO 2 to CO and CO to n ‐propanol, respectively, is constructed. Beyond the reported tandem electrodes and one‐pot tandem catalysts, precise voltage control over tandem electrolyzers enables optimizing the conversion of both CO 2 RR to CO and CORR to n ‐propanol. Significantly, an unprecedented Faradaic efficiency of 15.9% for n‐propanol along with corresponding half‐cell power conversion efficiency of 19.3% is achieved.