A review on CO₂ capture via nitrogen-doped porous polymers and catalytic conversion as a feedstock for fuels

The minimisation of the continuously enhancing level of the CO₂ released to the atmosphere is one of the most significant issues faced by the scientific community. Rigorous research efforts have been carried out for the development of sustainable and cost-effective nitrogen-rich porous adsorbent materials for energy-efficient and enhanced polar gas separation, i.e. pre-combustion and post-combustion CO₂ capture. Among different porous adsorbent materials, the covalent triazine frameworks (CTFs) are found to be remarkable candidates for CO₂ capturing because of their facile and scalable synthesis, high surface area, permanent porosity, structural tunability, synthetic diversity, low density, high hydrothermal and physicochemical stability. A contextual overview is described on the key challenges in CO₂ sequestration, parameters consideration for the design of CO₂ selective porous adsorbents, evaluation criteria for the adsorption processes, assessment criteria for the selection of suitable adsorption configuration, and the factors influencing the CO₂ adsorption capacity. This review comprises deep critical scrutiny of the current investigation and development on Triazine-, benzimidazole-, and triazole-based COPs with improved CO₂ storage capacities. The conversion of CO₂ into useful products including the carbon monoxide (CO), methane (CH₄), methanol (CH₃OH), and other products including the hydrocarbons has been critically reviewed by using the heterogeneous catalysis. Finally, a concise conclusion and recommendation section are presented indicating that the area of Triazine-, benzimidazole-, and triazole-based COPs for CO₂ capture needs more attention to synthesise the next-generation materials for real-time applications.