Kar Sayan, Goeppert Alain, Galvan Vicente, Chowdhury Ryan, Olah Justin, Prakash G K Surya
Loker Hydrocarbon Research Institute and Department of Chemistry , University of Southern California , University Park , Los Angeles , California 90089-1661 , United States.
J Am Chem Soc. 2018 Dec 12;140(49):16873-16876. doi: 10.1021/jacs.8b09325. Epub 2018 Oct 19.
A highly efficient recyclable system for capture and subsequent conversion of CO to formate salts is reported that utilizes aqueous inorganic hydroxide solutions for CO capture along with homogeneous pincer catalysts for hydrogenation. The produced aqueous solutions of formate salts are directly utilized, without any purification, in a direct formate fuel cell to produce electricity and regenerate the hydroxide base, achieving an overall carbon-neutral cycle. The catalysts and organic solvent are recycled by employing a biphasic solvent system (2-MTHF/HO) with no significant decrease in turnover frequency (TOF) over five cycles. Among different hydroxides, NaOH and KOH performed best in tandem CO capture and conversion due to their rapid rate of capture, high formate conversion yield, and high catalytic TOF to their corresponding formate salts. Among various catalysts, Ru- and Fe-based PNP complexes were the most active for hydrogenation. The extremely low vapor pressure, nontoxic nature, easy regenerability, and high reactivity of NaOH/KOH toward CO make them ideal for scrubbing CO even from low-concentration sources-such as ambient air-and converting it to value-added products.
报道了一种高效的可循环系统，用于捕获一氧化碳并随后将其转化为甲酸盐，该系统利用无机氢氧化物水溶液捕获一氧化碳，并使用均相钳形催化剂进行氢化反应。所生成的甲酸盐水溶液无需任何纯化，可直接用于直接甲酸盐燃料电池中发电并再生氢氧化物碱，从而实现整体碳中性循环。通过采用双相溶剂体系（2-甲基四氢呋喃/水），催化剂和有机溶剂得以循环利用，在五个循环中周转频率（TOF）没有显著下降。在不同的氢氧化物中，氢氧化钠和氢氧化钾在一氧化碳的串联捕获和转化方面表现最佳，这是由于它们的快速捕获速率、高甲酸盐转化率以及对相应甲酸盐的高催化TOF。在各种催化剂中，钌基和铁基PNP配合物对氢化反应最具活性。氢氧化钠/氢氧化钾极低的蒸气压、无毒性质、易于再生以及对一氧化碳的高反应活性，使其成为从低浓度源（如环境空气）中 scrubbing一氧化碳并将其转化为增值产品的理想选择。 （注：scrubbing此处存疑，结合语境可能是“去除、净化”之意，但原词较难准确对应合适中文）
