Anomalous Ru dissolution enabling efficient integrated CO2 electroreduction in strong acid

Recently, emerging acidic conditions CO2 electrolyzer overcomes the limitations of lower carbon utilization efficiency due to carbonate/bicarbonate formation in neutral/alkaline media, which offers a promising route to the realization of carbon cycle and environment optimization. Nevertheless, an integral CO2 conversion elec-trolyzer must consider the sluggish reaction kinetics of the oxygen evolution reaction (OER), especially in acid media. Herein, we demonstrate a significant improvement in anodic OER performance by tailoring the surface structure of RuO2 catalyst with potassium. The obtained K-RuO2 electrocatalyst can reach 10 mA/cm2 only with an overpotential of 170 mV and exhibits prolonged stability, showing overwhelming catalytic performance compared to RuO2. Advanced synchrotron radiation-based multi-techniques (SRMS) and theory calculations demonstrate the remarkable performance originating from the anomalous dissolution, which caused by consciously initiated K generating enhanced ratio of active RuCUS sites for K-RuO2. When K-RuO2 pairs with cathodic CO2RR catalyst of bismuth, it achieves the result of lower cell voltage and nearly 4-fold longer dura-bility in strong acid compared to RuO2 catalyst. This work provides a deep insight into the true active structure of anode RuO2 catalyst, paves a new way to design high-performance noble metal-based catalysts for acidic OER, and finally contributes to the advancement of CO2 electrolysis.