Sn-based gas diffusion electrodes (GDEs) are promising for electroreduction of CO₂ to formate (ERCF) as they can alleviate CO₂ mass transfer limitations. However, current electrodes suffer from large catalyst size or poor electron and/or ion connections. This limits ERCF performance. Here, we report a Sn-based GDE (IE-Sn) for ERCF fabricated via deposition of Sn nanoparticles onto a gas diffusion layer by using an impregnation-electroreduction method. The characterization results showed that the IE-Sn has small Sn catalyst size (16 nm) and excellent electronic and ionic transfer properties. Moreover, the faradaic efficiency (87.12 ± 4.28%) and partial current density for formate (62.79 ± 5.33 mA cm⁻²) obtained from the IE-Sn is 2.45-fold and 4.86-fold, respectively, of those of the traditional electrode. This ERCF performance is one of the best among recently reported Sn-based GDEs under similar conditions. Further analyses reveal that the enhanced ERCF performance of the IE-Sn is linked to the large electroactive surface area, enhanced adsorption capacity and chemisorption ability of CO₂, better stabilization of CO₂^.– intermediate, and excellent ion/electron transfer. This study offers design rules to fabricate high-performance electrode materials for ERCF.

锡基气体扩散电极（GDE）有望将CO ₂电还原为甲酸酯（ERCF），因为它们可以缓解CO ₂传质限制。然而，当前电极遭受催化剂尺寸大或电子和/或离子连接不良的困扰。这限制了ERCF的性能。在这里，我们报告了通过使用浸渍-电还原法将Sn纳米颗粒沉积到气体扩散层上而制备的ERCF的Sn基GDE（IE-Sn）。表征结果表明，IE-Sn具有较小的锡催化剂尺寸（16 nm），并且具有优异的电子和离子转移性能。此外，法拉第效率（87.12±4.28％）和甲酸的部分电流密度（62.79±5.33 mA cm ^-2）从IE-Sn获得的）分别是传统电极的2.45倍和4.86倍。在类似条件下，这种ERCF性能是最近报道的基于Sn的GDE中最好的之一。进一步的分析表明，IE-Sn的增强的ERCF性能与大的电活性表面积，增强的CO ₂吸附能力和化学吸附能力，更好的CO ₂稳定性有关^。–中等和出色的离子/电子转移。这项研究提供了设计规则，以制造用于ERCF的高性能电极材料。