Abstract：
Electrochemical carbon dioxide (CO2) reduction reaction (CO2RR) to valuable liquid fuels, such as formic acid/formate (HCOOH/HCOO-) is a promising strategy for carbon neutrality. Enhancing CO2RR activity while retaining high selectivity is critical for commercialization. To address this, we developed metal-doped bismuth (Bi) nanosheets via a facile hydrolysis method. These doped nanosheets efficiently generated high-purity HCOOH using a porous solid electrolyte (PSE) layer. Among the evaluated metal-doped Bi catalysts, Co-doped Bi demonstrated improved CO2RR performance compared to pristine Bi, achieving ~90 % HCOO- selectivity and boosted activity with a low overpotential of ~1.0 V at a current density of 200 mA cm-2. In a solid electrolyte reactor, Co-doped Bi maintained HCOOH Faradaic efficiency of ~72 % after a 100-hour operation under a current density of 100 mA cm-2, generating 0.1 M HCOOH at 3.2 V. Density functional theory (DFT) results revealed that Co-doped Bi required a lower applied potential for HCOOH generation from CO2, due to stronger binding energy to the key intermediates OCHO* compared to pure Bi. This study shows that metal doping in Bi nanosheets modifies the chemical composition, element distribution, and morphology, improving CO2RR catalytic activity performance by tuning surface adsorption affinity and reactivity.
摘要：
电化学二氧化碳（CO2）还原反应（CO2RR）到有价值的液体燃料，例如甲酸/甲酸(HCOOH/HCOO-)是碳中和的有前途的策略。增强CO-2RR活性同时保持高选择性对于商业化至关重要。为了解决这个问题，我们通过简单的水解方法开发了金属掺杂的铋（Bi）纳米片。这些掺杂的纳米片使用多孔固体电解质(PSE)层有效地产生高纯度HCOOH。在评估的金属掺杂Bi催化剂中，与原始Bi相比，共掺杂Bi表现出改善的CO2RR性能，在200mAcm-2的电流密度下，以〜1.0V的低超电势实现〜90％的HCOO选择性和增强的活性。在固体电解质反应器中，在100mAcm-2的电流密度下运行100小时后，共掺杂的Bi保持了〜72％的HCOOH法拉第效率，在3.2V时产生0.1MHCOOH。这项研究表明，Bi纳米片中的金属掺杂改变了化学组成，元素分布,和形态学，通过调节表面吸附亲和力和反应性提高CO2RR催化活性性能。
