Development of cerium-doped porous composite aerogel using cellulose nanocrystals for enhanced CO2 capture and conversion.

Abstract

Reducing carbon dioxide (CO₂) levels in the atmosphere is crucial for combating global warming. One effective strategy involves using porous materials for the combined processes of CO₂ capture and catalytic conversion. In this study, we developed composite aerogel materials using cellulose nanocrystals (CNCs) as templates, doped with cerium oxide, to enhance CO₂ capture and conversion. The CNCs possess a high specific surface area, which helps maintain the aerogel's internal structure, preventing the collapse of the silica aerogel during high-temperature calcination. This stability promotes CO₂ diffusion within the material, aiding in its reduction. Additionally, during high-temperature calcination, cerium nitrate decomposes into cerium oxide and nitrogen oxides, creating a network of micro-nano composite pores on the material's surface. The porous carbon materials exhibit excellent CO₂ adsorption capabilities, which are attributed to their rich and well-organized pore structures along with the synergistic effects of metal oxides. Our tests demonstrated that these materials have a high CO₂ adsorption capacity of 3.18 mmol/g and are capable of converting CO₂ into carbon monoxide and methane through photocatalytic reactions. This research offers new approaches for developing materials that integrate CO₂ capture with conversion processes.