Porous Bi Nanosheets Derived from β-Bi 2 O 3 for Efficient Electrocatalytic CO 2 Reduction to Formate.

The electrochemical CO 2 reduction reaction (ECO 2 RR) is a promising strategy for converting CO 2 into high-value chemical products. However, the synthesis of effective and stable electrocatalysts capable of transforming CO 2 into a specified product remains a huge challenge. Herein, we report a template-regulated strategy for the preparation of a Bi 2 O 3 -derived nanosheet catalyst with abundant porosity to achieve the expectantly efficient CO 2 -to-formate conversion. The resultant porous bismuth nanosheet ( p -Bi) not only exhibited marked Faradaic efficiency of formate ( FE formate ), beyond 91% in a broad potential range from -0.75 to -1.1 V in the H-type cell, but also demonstrated an appreciable FE formate of 94% at a high current density of 262 mA cm -2 in the commercially important gas diffusion cell. State-of-the-art X-ray absorption near edge structure spectroscopy (XANES) and theoretical calculation unraveled the distinct formate production performance of the p -Bi catalyst, which was cocontributed by its smaller size, plentiful porous structure, and stronger Bi-O bond, thus accelerating the absorption of CO 2 and promoting the subsequent formation of intermediates. This work provides an avenue to fabricate bismuth-based catalysts with high planar and porous morphologies for a broad portfolio of applications.