Perspectives on water-facilitated CO2 capture materials
Efficient separation of CO2 from other gases has become an issue of world-wide concern. Intrigued by the fascinating carbonic anhydrase-catalysed CO2 hydration and deprotonation in biological organisms, researchers have found that water can play a significant role in fast and selective CO2 transport (e.g. facilitating transport, salting-out effect, swelling, synergic sorption, etc.) and have managed to fabricate super CO2 capture materials by judiciously introducing water into solids. Considering that water usually exists in industrial CO2 resources and often acts as a negative impurity due to competitive sorption and pore blockage, exploring CO2 capture materials with the aid of water has become an important emerging strategy to provide general and excellent paradigms for practical CO2 capture technologies. In this sense, we propose a new concept, “water-facilitated CO2 capture (WFCC) materials”, which refers to solid materials (either adsorbents or membranes) with a remarkable improvement in CO2 capture performance due to entrapped water. In this way, we endeavor to answer an important question: when and how water contributes to this drastic enhancement. Strategies to avoid the negative effects of water and to enable WFCC are also tentatively proposed.