Waste foam to upcycled sponge-like porous carbon composites for efficient CO2 capture and conversion

Waste-derived porous carbon shows great potential for application in CO2 capture and conversion. In this work, we report a modified method for upcycling waste foam from vehicular sound insulation materials into porous carbon fiber composites that can be used for efficient CO2 capture and conversion under 1 bar conditions. The sponge-like porous carbon composites have high nitrogen content, porosity, and mechanical strength, and can selectively adsorb CO2 from flue gas. The adsorbed CO2 can be desorbed via heating or vacuum and then converted into useful products such as cyclic carbonates. Besides, sponge-like porous carbon composites show good stability and recyclability, and can be easily scaled up in industrial applications. It is important to note that high-temperature carbonization causes the loss of nitrogen in unmodified porous carbon materials, which makes physical adsorption the dominant type of CO2 adsorption. In contrast, composite materials that have undergone in-situ polymerization primarily adsorb and activate CO2 through chemical action. The results of BET, XPS, TEM, FT-IR, and DFT studies suggest that the modified sponge-like porous carbon composites with more active sites are beneficial for CO2 capture and conversion. Therefore, this study provides a green and sustainable way to utilize waste foam from end-of-life vehicles and the value-increment of CO2.