Nitrogen-Rich Porous-Conjugated Framework for Efficient Capture and Electroreduction of Simulated Flue Gas in Acidic Electrolyte

Achieving the integration of simulated flue gas catalysis with acidic eCO₂RR represents a highly promising and economically viable strategy for industrialization, yet remains unexplored. Here, with the design of a nitrogen-rich conjugated framework (CAU-35), we first report the successful demonstration of highly efficient conversion of simulated flue gas to formic acid in an acidic environment, while further unveiling a novel mechanism of protonation-enhanced adsorption. Through the integrated construction of capture and catalysis, the system can achieve an unprecedented Faradaic efficiency of 96.6% for formic acid production and a remarkable single-pass conversion efficiency up to 71.4% in a flow cell, surpassing the performance of conventional alkaline systems and those utilizing pure CO₂ as a feedstock. Moreover, comparative studies with the nitrogen-free analogue (CAU-7) unequivocally demonstrate that the anomalous enhancement in acidic acid stems from material protonation. Further complemented by molecular dynamics simulations, the novel mechanism is uncovered by which material protonation can enhance CO₂ adsorption and catalytic performance via optimization of interfacial interaction. These fundamental insights provide critical principles for system optimization and microenvironmental design, paving the way for the practical implementation of eCO₂RR technologies.