Addressing the Carbonate Issue: Electrocatalysts for Acidic CO₂ Reduction Reaction

AbstractElectrochemical CO2 reduction reaction (CO2RR) powered by renewable energy provides a promising route to CO2 conversion and utilization. However, the widely used neutral/alkaline electrolyte consumes a large amount of CO2 to produce (bi)carbonate byproducts, leading to significant challenges at the device level, thereby impeding the further deployment of this reaction. Conducting CO2RR in acidic electrolytes offers a promising solution to address the “carbonate issue”; however, it presents inherent difficulties due to the competitive hydrogen evolution reaction, necessitating concerted efforts towards advanced catalyst and electrode designs to achieve high selectivity and activity. This review encompasses recent developments of acidic CO2RR, from mechanism elucidation to catalyst design and device engineering. We begin by discussing the mechanistic understanding of the reaction pathway, laying the foundation for catalyst design in acidic CO2RR. Subsequently, we provide an in‐depth analysis of recent advancements in acidic CO2RR catalysts, highlighting heterogeneous catalysts, surface immobilized molecular catalysts and catalyst surface enhancement. Furthermore, we summarize the progress made in device‐level applications, aiming to develop high‐performance acidic CO2RR systems. Finally, we outline the existing challenges and future directions in the design of acidic CO2RR catalysts, emphasizing the need for improved selectivity, activity, stability, and scalability.This article is protected by copyright. All rights reserved