Ion-crosslinking induced dynamic assembly of porous 3D graphene oxide framework for CO2 capture

Abstract

Gas adsorbent demonstrates a high importance in the reduction of CO2 emission while graphene oxide (GO) is a promising 2D material for CO2 adsorption for its high theoretical surface area and abundant oxygen-containing functional groups distributed on the 2D nanosheet. However, the current gas adsorption capability lags largely behind the ideal value, arising from the aggregation and restacking of GO nanosheets hindering the exposure of adsorption sites. Here, the ‘ionic-crosslinking induced dynamic assembly coupled ice-templating’ (IDAI) strategy was employed to fabricate the porous 3D GO framework for CO2 capture, which could alleviate the aggregation and restacking issue of GO nanosheets during fabrication by the ionic crosslinking. The fabricated 3D GO microstructure can be adjusted by controlling the dynamic assembly process by changing the GO concentration. After optimization, the porous 3D GO adsorbent offers a CO2 adsorption capacity of 2.24 mmol/g at ambient pressure and temperature with good running stability, attributed to the strong ionic crosslinking. More importantly, the proposed method shows the generality of many multivalent cations, which constructs a versatile platform for GO microstructure tailoring.