Yuvraj Y. Birdja

Electrochemical CO ₂ reduction (eCO ₂ R) offers a sustainable route for carbon utilization, but most electrolyzers operate in neutral or alkaline media, where (bi)carbonate formation limits long‐term operation and complicates product recovery. Here, we show that operating eCO ₂ R under acidic conditions enables direct formic acid production while minimizing (bi)carbonate accumulation. A eutectic Bi–Sn gas‐diffusion electrode (GDE) achieved a faradaic efficiency (FE) of 81.3% toward formic acid at −100 mA cm ⁻² and in a pH 3 electrolyte, outperforming Bi and Sn GDEs, with formic acid remaining the dominant product up to −400 mA cm ⁻² . Density functional theory calculations revealed a synergistic Bi–Sn interfacial effect, where weakened hydrogen adsorption and intermediate binding of CO ₂ ‐to‐formate intermediates collectively suppress hydrogen evolution and promote formic acid formation. The GDE maintained stable performance with 2 R as a viable strategy for high‐purity formic acid production and demonstrate how interfacial alloy engineering can advance CO ₂ electrolysis toward scalable, renewable energy‐powered chemical manufacturing.

This review summarizes advances in CO ₂ electrocatalysis, from homogeneous to heterogeneous systems, with emphasis on hybrid molecular–metallic co-catalysts that drive improved activity, selectivity, and overall catalytic performance.

Electrochemical CO ₂ reduction (ECR) to formate/formic acid (FA) represents one of the most viable pathways for converting CO ₂ into value-added chemicals, particularly under industrially relevant conditions.

The energy transition and electrification of the chemical industry necessitate electrocatalytic processes which have rapidly increased in interest over the past years. However, to have a sustainable impact on society and environment, industrial realization of the electrocatalytic processes is ultimately required. Since the stability parameter becomes more important in view of upscaling electrocatalytic processes, it is essential that researchers know about seemingly innocent procedures affecting the interpretation of faradaic efficiency and stability. We use the electrocatalytic reduction of CO₂ to highlight important pitfalls and hidden ambiguities caused by improper experimental/mathematical procedures related to the calculation of faradaic efficiency, and critically discuss alternatives for a better assessment of electrocatalyst stability. The acquired insights are a first attempt to quantify and better evaluate electrocatalyst stability in order to improve comparability of experimental results and to optimize electrocatalysts or process conditions for durable performance.