Advance in Novel Device Design and Microenvironment Modulation for Bismuth‐Based CO 2 ‐to‐ Formic Acid Electrocatalysis

Abstract The electrochemical CO 2 reduction reaction (CO 2 RR) driven by renewable energy to produce formic acid (FA) is one of the key pathways toward achieving carbon neutrality. Bi‐based materials have emerged as leading candidates among the diverse range of CO 2 reduction catalysts due to their high activity, excellent selectivity, and relative abundance. Despite these advantages, their practical application is hindered by several critical challenges, including significant CO 2 crossover losses, carbonate precipitation that deactivates active sites, and the production of low‐purity FA, which necessitates resource‐intensive separation processes. This review surveys the benefits, advantages, and challenges of Bi‐catalyzed CO 2 RR to form FA. Then, innovative strategies to overcome the barriers in Bi‐catalyzed CO 2 RR systems are systematically explored, focusing on advancements in electrolyte modulation and device design. These key approaches include: 1) the adoption of acidic electrolytes, 2) the implementation of solid‐state electrolytes (SSEs), and 3) the integration of bipolar membranes (BPM), thereby improving FA efficiency and device durability of Bi‐based CO 2 RR. Finally, we provide a brief outlook on the future opportunities for these technologies to accelerate the industrialization of CO 2 RR to FA.