Recent progress of Bi-based electrocatalysts for electrocatalytic CO 2 reduction.

To mitigate excessively accumulated carbon dioxide (CO 2 ) in the atmosphere and tackle the associated environmental concerns, green and effective approaches are necessary. The electrocatalytic CO 2 reduction reaction (CO 2 RR) using sustainable electricity under benign reaction conditions represents a viable way to produce value-added and profitable chemicals. In this minireview, recent studies regarding unary Bi electrocatalysts and binary BiSn electrocatalysts are symmetrically categorized and reviewed, as they disclose high faradaic efficiencies toward the production of formate/formic acid, which has a relatively higher value of up to 0.50 $·per kg and has been widely used in the chemical and pharmaceutical industry. In particular, the preparation methodologies, electrocatalyst morphologies, catalytic performances and the corresponding mechanisms are comprehensively presented. The use of solid-state electrolytes showing high economic prospects for directly obtaining high-purity formic acid is highlighted. Finally, the remaining questions and challenges for CO 2 RR exploitations using Bi-related electrocatalysts are proposed, while perspectives and the corresponding strategies aiming to enhance their entire catalytic functionalities and boost their performance are provided.