Department of Chemistry, Stanford University, Stanford, California 94305 United States.
J Am Chem Soc. 2022 Sep 21;144(37):16744-16748. doi: 10.1021/jacs.2c07779. Epub 2022 Sep 8.
We report the use of 1,2,3-triazole (Tz)-containing water microdroplets for gas-phase carbon dioxide (CO) reduction at room temperature. Using a coaxial sonic spraying setup, the CO can be efficiently captured by Tz and converted to formic acid (HCOOH; FA) at the gas-liquid interface (GLI). A mass spectrometer operated in negative ion mode monitors the capture of CO to form the bicarbonate anion (HCO) and conversion to form the formate anion (HCOO). Varied FA species were successfully identified by MS/MS experiments including the formate monomer ([FA - H], / 45), the dimer ([2FA - H], / 91; [2FA + Na - 2H], / 113), the trimer ([3FA - H], / 137), and some other adducts (such as [FA - H + HCO], / 107; [2FA + Na - 2H + Tz], / 182). The reaction conditions were systematically optimized to make the maximum conversion yield reach over 80% with an FA concentration of approximately 71 ± 3.1 μM. The mechanism for the reaction is speculated to be that Tz donates the proton and the hydroxide (OH) at the GLI, resulting in a stepwise yield of electrons to reduce gas-phase CO to FA.
我们报告了使用含 1,2,3-三唑 (Tz) 的水微滴在室温下进行气相二氧化碳 (CO) 还原。使用同轴超声喷涂装置，CO 可以被 Tz 有效捕获，并在气液界面 (GLI) 转化为甲酸 (HCOOH; FA)。质谱仪在负离子模式下运行，监测 CO 的捕获以形成碳酸氢根阴离子 (HCO)，并转化为甲酸盐阴离子 (HCOO)。通过 MS/MS 实验成功鉴定了不同的 FA 物种，包括甲酸盐单体 ([FA - H], / 45)、二聚体 ([2FA - H], / 91; [2FA + Na - 2H], / 113)、三聚体 ([3FA - H], / 137) 和一些其他加合物（如 [FA - H + HCO], / 107; [2FA + Na - 2H + Tz], / 182）。系统地优化了反应条件，使最大转化率达到 80%以上，FA 浓度约为 71 ± 3.1 μM。推测反应的机理是 Tz 在 GLI 上提供质子和氢氧根 (OH)，导致气相 CO 逐步还原为 FA 的电子产量增加。
