Wang Yang, Feric Tony G, Tang Jing, Fang Chao, Hamilton Sara T, Halat David M, Wu Bing, Celik Hasan, Rim Guanhe, DuBridge Tara, Oshiro Julianne, Wang Rui, Park Ah-Hyung Alissa, Reimer Jeffrey A
Department of Chemical and Biomolecular Engineering, College of Chemistry, UC Berkeley, Berkeley, CA 94720, USA.
Department of Chemical Engineering, Columbia University, New York, NY 10027, USA.
Sci Adv. 2024 Apr 19;10(16):eadk2350. doi: 10.1126/sciadv.adk2350.
Nanoparticle organic hybrid materials (NOHMs) have been proposed as excellent electrolytes for combined CO capture and electrochemical conversion due to their conductive nature and chemical tunability. However, CO capture behavior and transport properties of these electrolytes after CO capture have not yet been studied. Here, we use a variety of nuclear magnetic resonance (NMR) techniques to explore the carbon speciation and transport properties of branched polyethylenimine (PEI) and PEI-grafted silica nanoparticles (denoted as NOHM-I-PEI) after CO capture. Quantitative C NMR spectra collected at variable temperatures reveal that absorbed CO exists as carbamates (RHNCOO or RR'NCOO) and carbonate/bicarbonate (CO/HCO). The transport properties of PEI and NOHM-I-PEI studied using H pulsed-field-gradient NMR, combined with molecular dynamics simulations, demonstrate that coulombic interactions between negatively and positively charged chains dominate in PEI, while the self-diffusion in NOHM-I-PEI is dominated by silica nanoparticles. These results provide strategies for selecting adsorbed forms of carbon for electrochemical reduction.
纳米颗粒有机杂化材料（NOHMs）因其导电性质和化学可调性，已被提议作为用于联合二氧化碳捕集和电化学转化的优异电解质。然而，这些电解质在捕集二氧化碳后的二氧化碳捕集行为和传输性质尚未得到研究。在此，我们使用多种核磁共振（NMR）技术来探究支化聚乙烯亚胺（PEI）和PEI接枝的二氧化硅纳米颗粒（记为NOHM-I-PEI）在捕集二氧化碳后的碳形态和传输性质。在可变温度下收集的定量碳核磁共振谱表明，吸附的二氧化碳以氨基甲酸盐（RHNCOO或RR'NCOO）和碳酸盐/碳酸氢盐（CO/HCO）的形式存在。使用氢脉冲场梯度核磁共振结合分子动力学模拟研究的PEI和NOHM-I-PEI的传输性质表明，带负电和带正电的链之间的库仑相互作用在PEI中占主导，而NOHM-I-PEI中的自扩散则由二氧化硅纳米颗粒主导。这些结果为选择用于电化学还原的碳吸附形式提供了策略。
