Sustainable hierarchical porous carbon aerogel from cellulose for high-performance supercapacitor and CO2 capture

•Porous cellulose carbon aerogels were obtained via carbonized and activated simultaneously.•Cellulose carbon aerogel had a high specific surface area of 1364m2/g and a high specific capacitance of 328Fg−1.•For the first time, we showed that the cellulose carbon aerogel had a good CO2 adsorption capacity.