School of Chemistry and Biosciences , University of Bradford , Bradford BD7 1DP , United Kingdom.
Facultatea de Chimie şi Inginerie Chimică , Universitatea Babeş-Bolyai , Cluj-Napoca 400084 , Romania.
ACS Appl Mater Interfaces. 2018 Apr 25;10(16):13693-13701. doi: 10.1021/acsami.8b01776. Epub 2018 Apr 13.
Carbon monoxide (CO) is both a substance hazardous to health and a side product of a number of industrial processes, such as methanol steam reforming and large-scale oxidation reactions. The separation of CO from nitrogen (N) in industrial processes is considered to be difficult because of the similarities of their electronic structures, sizes, and physicochemical properties (e.g., boiling points). Carbon monoxide is also a major poison in fuel cells because of its adsorption onto the active sites of the catalysts. It is therefore of the utmost economic importance to discover new materials that enable effective CO capture and release under mild conditions. However, methods to specifically absorb and easily release CO in the presence of contaminants, such as water, nitrogen, carbon dioxide, and oxygen, at ambient temperature are not available. Here, we report the simple and versatile fabrication of a new class of hybrid materials that allows capture and release of carbon monoxide under mild conditions. We found that carborane-containing metal complexes encapsulated in networks made of poly(dimethylsiloxane) react with CO, even when immersed in water, leading to dramatic color and infrared signature changes. Furthermore, we found that the CO can be easily released from the materials by simply dipping the networks into an organic solvent for less than 1 min, at ambient temperature and pressure, which not only offers a straightforward recycling method, but also a new method for the "on-demand" release of carbon monoxide. We illustrated the utilization of the on-demand release of CO from the networks by carrying out a carbonylation reaction on an electron-deficient metal complex that led to the formation of the CO-adduct, with concomitant recycling of the gel. We anticipate that our sponge-like materials and scalable methodology will open up new avenues for the storage, transport, and controlled release of CO, the silent killer and a major industrial poison.
一氧化碳（CO）既是一种对健康有害的物质，也是许多工业过程的副产物，如甲醇蒸汽重整和大规模氧化反应。由于其电子结构、大小和物理化学性质（如沸点）相似，因此从工业过程中分离 CO 和氮气（N）被认为是困难的。一氧化碳也是燃料电池中的主要毒物，因为它会吸附在催化剂的活性位上。因此，发现能够在温和条件下有效捕获和释放 CO 的新材料具有极其重要的经济意义。然而，目前还没有方法可以在环境温度下，针对存在水、氮气、二氧化碳和氧气等污染物的情况下，专门吸收和容易释放 CO。在这里，我们报告了一种新型杂化材料的简单而通用的制造方法，该方法可以在温和条件下实现 CO 的捕获和释放。我们发现，即使在水中浸泡，含有 carborane 的金属配合物封装在由聚二甲基硅氧烷制成的网络中也会与 CO 反应，导致明显的颜色和红外特征变化。此外，我们发现，只需将网络简单浸入有机溶剂中不到 1 分钟，即可在环境温度和压力下从材料中轻松释放 CO，这不仅提供了一种简单的回收方法，还提供了一种新的“按需”释放 CO 的方法。我们通过对缺电子金属配合物进行羰基化反应来展示从网络中按需释放 CO 的利用，从而形成 CO 加合物，并同时回收凝胶。我们预计，我们的海绵状材料和可扩展的方法将为 CO 的存储、运输和控制释放开辟新途径，CO 是一种无声杀手和主要的工业毒物。
