Bridging polymer design with catalyst surface science is a promising direction for tuning and optimizing electrochemical reactors that could impact long-term goals in energy and sustainability. Particularly, the interaction between inorganic catalyst surfaces and organic-based ionomers provides an avenue to both steer reaction selectivity and promote activity. Here, we studied the role of imidazolium-based ionomers for electrocatalytic CO₂ reduction to CO (CO₂R) on Ag surfaces and found that they produce no effect on CO₂R activity yet strongly promote the competing hydrogen evolution reaction (HER). By examining the dependence of HER and CO₂R rates on concentrations of CO₂ and HCO₃^–, we developed a kinetic model that attributes HER promotion to intrinsic promotion of HCO₃^– reduction by imidazolium ionomers. We also show that varying the ionomer structure by changing substituents on the imidazolium ring modulates the HER promotion. This ionomer-structure dependence was analyzed via Taft steric parameters and density functional theory calculations, which suggest that steric bulk from functionalities on the imidazolium ring reduces access of the ionomer to both HCO₃^– and the Ag surface, thus limiting the promotional effect. Our results help develop design rules for ionomer–catalyst interactions in CO₂R and motivate further work into precisely uncovering the interplay between primary and secondary coordination in determining electrocatalytic behavior.

中文翻译：

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用咪唑鎓离聚物对银催化剂表面进行化学改性，调节电化学 CO2 还原过程中的 H2 释放速率

将聚合物设计与催化剂表面科学相结合是调整和优化电化学反应器的一个有前途的方向，这可能会影响能源和可持续性的长期目标。特别是，无机催化剂表面和有机基离聚物之间的相互作用为控制反应选择性和促进活性提供了途径。在这里，我们研究了基于咪唑鎓的离聚物在 Ag 表面电催化CO ₂还原为 CO (CO ₂ R) 中的作用，发现它们对 CO ₂ R 活性没有影响，但强烈促进了竞争性析氢反应 (HER)。通过检查 HER 和 CO ₂ R 速率对 CO ₂和 HCO ₃浓度的依赖性^–，我们开发了一个动力学模型，将 HER 促进归因于 HCO _{3 的}内在促进^-咪唑鎓离聚物的还原。我们还表明，通过改变咪唑环上的取代基来改变离聚物结构可调节 HER 促进。这种离聚物结构依赖性经由塔夫脱空间参数和密度泛函理论计算，这表明，空间体积从咪唑鎓环上的功能降低了离聚物的同时访问HCO分析₃ ^-和银表面，从而限制了促销效果。我们的结果有助于制定 CO _{2 中}离聚物-催化剂相互作用的设计规则R 并激发进一步的工作，以精确揭示确定电催化行为的初级和次级配位之间的相互作用。