Synthesis of hierarchical meso‐macroporous silica monolith using chitosan as biotemplate and its application as polyethyleneimine support for CO2 capture

► Chitosan for the first time as biotemplate in the synthesis of silica monolith. ► Crack-free silica monolith having bimodal pores in different length scales. ► PEI-loaded silica monolith exhibits several good properties for CO2 capture.