Zhou Zhi-Hua, Chen Kai-Hong, Gao Song, Yang Zhi-Wen, He Liang-Nian
State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
Research (Wash D C). 2020 Sep 25;2020:9398285. doi: 10.34133/2020/9398285. eCollection 2020.
In the photoreduction of CO to CO, the competitive H evolution is always inevitable due to the approximate reduction potentials of H/H and CO/CO, which results in poor selectivity for CO production. Herein, imidazolium-type ionic liquid- (IL-) modified rhenium bipyridine-based porous organometallic polymers (Re-POMP-IL) were designed as efficient and selective photocatalysts for visible-light CO photoreduction to CO based on the affinity of IL with CO. Photoreduction studies demonstrated that CO photoreduction promoted by Re-POMP-IL functioning as the catalyst exhibits excellent CO selectivity up to 95.5% and generate 40.1 mmol CO/g of Re-POMP-IL1.0 (obtained by providing equivalent [(5,5'-divinyl-2,2'-bipyridine)Re(CO)Cl] and 3-ethyl-1-vinyl-1-imidazol-3-ium bromide) at 12 h, outperforming that attained with the corresponding Re-POMP analogue without IL, which highlights the crucial role of IL. Notably, CO adsorption, light harvesting, and transfer of photogenerated charges as key steps for CORR were studied by employing POMPs modified with different amounts of IL as photocatalysts, among which the CO affinity as an important factor for POMPs catalyzed CO reduction is revealed. Overall, this work provides a practical pathway to improve the CO photoreduction efficiency and CO selectivity by employing IL as a regulator.
在将CO光还原为CO的过程中，由于H⁺/H₂和CO₂/CO的还原电位相近，竞争性析氢总是不可避免的，这导致CO生成的选择性较差。在此，基于咪唑鎓型离子液体（IL）与CO的亲和力，设计了咪唑鎓型离子液体修饰的铼联吡啶基多孔有机金属聚合物（Re-POMP-IL），作为可见光将CO₂光还原为CO的高效且选择性的光催化剂。光还原研究表明，以Re-POMP-IL为催化剂促进的CO₂光还原表现出高达95.5%的优异CO选择性，在12小时内每克Re-POMP-IL1.0（通过提供等量的[(5,5'-二乙烯基-2,2'-联吡啶)Re(CO)Cl]和3-乙基-1-乙烯基-1-咪唑鎓溴化物获得）可生成40.1 mmol CO，优于相应未修饰IL的Re-POMP类似物，这突出了IL的关键作用。值得注意的是，通过使用不同IL含量修饰的POMPs作为光催化剂，研究了CO吸附、光捕获和光生电荷转移作为CO₂RR的关键步骤，其中揭示了CO亲和力是POMPs催化CO₂还原的一个重要因素。总体而言，这项工作提供了一条通过使用IL作为调节剂来提高CO₂光还原效率和CO选择性的实用途径。
