Electrocatalytic CO₂ reduction to formate is considered as a perfect route for efficient conversion of the greenhouse gas CO₂ to value-added chemicals. However, it still remains a huge challenge to design a catalyst with both high catalytic activity and selectivity for target products. Here we report a unique Sn-doped Bi₂O₃ nanosheet (NS) electrocatalyst with different atomic percentages of Sn (1.2, 2.5, and 3.8%) prepared by a simple solvothermal method for highly efficient electrochemical reduction of CO₂ to formate. Of them, the 2.5% Sn-doped Bi₂O₃ NSs exhibited the highest faradaic efficiency (FE) of 93.4% with a current density of 24.3 mA cm⁻² for formate at −0.97 V in the H-cell and a maximum current density of nearly 50 mA cm⁻² was achieved at −1.27 V. The formate FE is stable maintained at over 90% in a wide potential range from −0.87 V to −1.17 V. Electrochemical and density functional theory (DFT) analyses of undoped and Sn doped Bi₂O₃ NSs indicated that the strong synergistic effect between Sn and Bi is responsible for the enhancement in the adsorption capacity of the OCHO* intermediate, and thus the activity for formate production. In addition, we coupled 2.5% Sn-doped Bi₂O₃ NSs with a dimensionally stable anode (DSA) to realize battery-driven highly active CO₂RR and OER with decent activity and efficiency.

中文翻译：

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Sn 掺杂的 Bi2O3 纳米片用于高效的电化学 CO2 还原以生产甲酸盐

电催化 CO ₂还原为甲酸盐被认为是将温室气体 CO ₂有效转化为高附加值化学品的完美途径。然而，设计一种对目标产物具有高催化活性和选择性的催化剂仍然是一个巨大的挑战。在这里，我们报告了一种独特的掺杂 Sn 的 Bi ₂ O ₃纳米片 (NS) 电催化剂，该催化剂具有不同的 Sn 原子百分比（1.2、2.5 和 3.8%），该催化剂通过简单的溶剂热法制备，用于高效电化学还原 CO ₂以形成甲酸盐。其中，掺杂 2.5% Sn 的 Bi ₂ O ₃ NSs 表现出最高的法拉第效率 (FE)，为 93.4%，电流密度为 24.3 mA cm^-2用于 H 电池中 -0.97 V 的甲酸盐，在 -1.27 V 时实现了近 50 mA cm ^-2的最大电流密度。甲酸盐 FE 在 -0.87 的宽电位范围内稳定保持在 90% 以上V 至 -1.17 V。未掺杂和掺杂 Sn 的 Bi ₂ O ₃ NSs 的电化学和密度泛函理论 (DFT) 分析表明，Sn 和 Bi 之间的强协同作用是提高 OCHO* 中间体吸附能力的原因，以及甲酸盐生产活动。此外，我们将 2.5% Sn 掺杂的 Bi ₂ O ₃ NSs 与尺寸稳定的阳极 (DSA) 结合以实现电池驱动的高活性 CO ₂具有良好活动和效率的 RR 和 OER。