BiOx shows promising selectivity in catalyzing the electrochemical reduction of CO2 to formate, but the process suffers from high overpotential and a low rate. Moreover, the active sites are still ambiguous under electrochemical conditions. Herein, we introduce Mn-doping to enhance the activity of binder-free Bi2O3 and elaborate on active sites through in situ Raman and density functional theory (DFT) analyses. The Mn-doped Bi2O3 transforms to Mn-doped Bi2(CO3)O2 in KHCO3 and subsequently reduces to Mn-modified metallic Bi under cathodic potentials. The undoped Bi2O3 is found to follow the same phase transitions but at a different rate. The DFT analyzes the impact of doping the Bi(012) with Mn and indicates significantly improved selectivity for formate generation. Further, the importance of the substrate’s hydrophobicity for long-term stability is demonstrated. This study offers in-depth insights into the design and understanding of doped BiOx-based electrodes for CO2 reduction.

中文翻译：

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在 PTFE 处理的碳纸上生长的 Mn 掺杂 Bi2O3 用于电化学 CO2 制甲酸盐生产


BiOx 在催化 CO2 电化学还原为甲酸盐方面显示出有希望的选择性，但该过程存在高过电位和低速率的问题。此外，在电化学条件下，活性位点仍然不明确。在此，我们引入了 Mn 掺杂以增强无粘合剂 Bi2O3 的活性，并通过原位拉曼和密度泛函理论 （DFT） 分析详细说明了活性位点。Mn 掺杂的 Bi2O3 在 KHCO3 中转化为 Mn 掺杂的 Bi2（CO3）O2，随后在阴极电位下还原为 Mn 修饰的金属 Bi。发现未掺杂的 Bi2O3 遵循相同的相变，但速率不同。DFT 分析了用 Mn 掺杂 Bi（012） 的影响，并表明甲酸盐生成的选择性显着提高。此外，还证明了基材的疏水性对长期稳定性的重要性。本研究为设计和理解用于 CO2 还原的掺杂 BiOx 基电极提供了深入的见解。