Binford Trevor B, Mapstone Grace, Temprano Israel, Forse Alexander C
Department of Chemistry, University of Cambridge, Lensfield Road, CB2 1EW, UK.
Nanoscale. 2022 Jun 9;14(22):7980-7984. doi: 10.1039/d2nr00748g.
Supercapacitive swing adsorption (SSA) is a recently discovered electrochemically driven CO capture technology that promises significant efficiency improvements over traditional methods. A limitation of this approach is the relatively low CO adsorption capacity, and the underlying molecular mechanisms of SSA remain poorly understood, hindering optimization. Here we present a new device architecture for simultaneous electrochemical and gas-adsorption measurements, and use it to investigate the effects of charging protocols on SSA performance. We show that altering the voltage applied to charge the SSA device can significantly improve performance. Charging the gas-exposed electrode positively rather than negatively increases CO adsorption capacity and causes CO desorption rather than adsorption with charging. We also show that switching the voltage between positive and negative values further increases CO capacity. Previously proposed mechanisms of the SSA effect fail to explain these phenomena, so we present a new mechanism based on movement of CO-derived species into and out of electrode micropores. Overall, this work advances our knowledge of electrochemical CO adsorption by supercapacitors, potentially leading to devices with increased uptake capacity and efficiency.
超级电容摆动吸附（SSA）是一种最近发现的电化学驱动的CO捕获技术，有望比传统方法显著提高效率。这种方法的一个局限性是CO吸附容量相对较低，并且SSA的潜在分子机制仍知之甚少，这阻碍了优化。在这里，我们展示了一种用于同时进行电化学和气体吸附测量的新设备架构，并使用它来研究充电协议对SSA性能的影响。我们表明，改变施加在SSA设备上的充电电压可以显著提高性能。对暴露于气体的电极进行正向充电而不是负向充电会增加CO吸附容量，并导致充电时CO解吸而不是吸附。我们还表明，在正值和负值之间切换电压会进一步提高CO容量。先前提出的SSA效应机制无法解释这些现象，因此我们提出了一种基于CO衍生物种进出电极微孔运动的新机制。总体而言，这项工作推进了我们对超级电容器电化学CO吸附的认识，有可能导致具有更高吸收容量和效率的设备。
