Chitosan-Based Porous Carbon Materials with Built-In Lewis Acid Boron Sites for Enhanced CO₂ Capture and Conversion via an Electron-Inducing Effect

Electron-induced effects, which are prevalent in adsorption and heterogeneous catalytic reactions, can significantly influence the state and uptake of adsorbates. Here, we demonstrate the in situ doping of electron-deficient boron into the backbone of chitosan-based porous carbon materials. Despite a reduction in specific surface area, the resulting boron-doped porous carbons (NBPCs) exhibit an enhanced CO₂ adsorption performance, with sample NBPC-10 achieving CO₂ adsorption capacities of 7.62 and 4.82 mmol·g^-1 at 273 and 298 K, respectively. This improvement is attributed to the electron-induced effect of boron doping, which also enhances the separation selectivity of CO₂ from N₂. Additionally, the high CO₂ adsorption capacity fosters synergism between NBPCs and the cocatalyst tetrabutylammonium bromide (TBAB), thereby augmenting the catalytic activity for the cycloaddition of CO₂ and epoxide. Notably, cyclic carbonate yields exceeding 99% were attained even under 1 bar of CO₂. Controlled experiments corroborated the pivotal role of boron-doping-induced modifications in the porous carbon structure in enhancing both CO₂ selective adsorption and conversion performance. Furthermore, NBPCs demonstrated excellent recyclability as both adsorbents and catalysts, offering fresh perspectives for the design of functionalized porous carbon materials tailored for CO₂ capture and conversion.