Li Jiachen, Guo Jinyu, Dai Hongjie
Department of Chemistry and Bio-X, Stanford University, Stanford, CA 94305, USA.
Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA.
Sci Adv. 2022 May 13;8(19):eabo0399. doi: 10.1126/sciadv.abo0399.
CO dissolved in aqueous solutions CO(aq) is important to CO capture, storage, photo-/electroreduction in the fight against global warming and to CO analysis in drinks. Here, we developed microscale infrared (IR) spectroscopy for in situ dynamic quantitating CO(aq). The quantized CO(g) rotational state transitions were observed to quench for CO(aq), accompanied by increased HO IR absorption. An accurate CO molar extinction coefficient ε was derived for in situ CO(aq) quantification up to 58 atm. We directly measured CO(aq) concentrations in electrolytes under CO(g) bubbling and high-pressure conditions with high spectral and time resolutions. In KHCO electrolytes with CO(aq) > ~1 M, CO electroreduction (CORR) to formate reached >98% Faradaic efficiencies on copper (CuO/Cu)-based electrocatalyst. Furthermore, CO dissolution/desolvation kinetics showed large hysteresis and ultraslow reversal of CO(aq) supersaturation in aqueous systems, with implications to CO capture, storage, and supersaturation phenomena in natural water bodies.
溶解于水溶液中的一氧化碳（CO(aq)）对于CO捕获、储存、光/电还原以应对全球变暖以及饮料中的CO分析都很重要。在此，我们开发了用于原位动态定量CO(aq)的微尺度红外（IR）光谱。观察到CO(g)的量子化转动状态跃迁因CO(aq)而猝灭，同时伴随着HO红外吸收的增加。推导出了准确的CO摩尔消光系数ε，用于高达58个大气压的原位CO(aq)定量。我们在高光谱和时间分辨率下直接测量了CO(g)鼓泡和高压条件下电解质中的CO(aq)浓度。在CO(aq) > ~1 M的KHCO电解质中，在基于铜（CuO/Cu）的电催化剂上，CO电还原为甲酸盐的法拉第效率达到>98%。此外，CO溶解/去溶剂化动力学显示出较大的滞后现象以及水溶液体系中CO(aq)过饱和的超慢逆转，这对天然水体中的CO捕获、储存和过饱和现象具有启示意义。
