Electrochemical CO₂ conversion to fuels on metal-free N-doped carbon-based materials: functionalities, mechanistic, and technoeconomic aspects

Alarming levels of carbon dioxide (CO₂) emission are increasingly posing calamitous consequences of environmental destruction and climate change. CO₂ reduction reactions (CO₂RRs) to fuels are both kinetically and thermodynamically unfavorable. This necessitates cleaner technologies for addressing the root cause of this notorious gas and its negative outcome, which has become a complex global phenomenon. The N-doped carbon-based electrocatalysts remain the emergent class of novel, safe, efficient, earth-abundant carbon, and ecofriendly for CO₂ conversion to fuels and chemicals. N-doping modifies the electronic properties of carbon materials to enhance the electrocatalytic CO₂RR to useful products and offers high activity, selectivity, and efficiency by suitably tuning the N species. This study presents recent advancements on the N-doped carbon-based electrocatalysts for CO₂RR. The first few parts present the uniqueness of N-doped carbon-based electrocatalysts prior to the methodology of N-doping and N-doped electrocatalytic active sites. These were followed by recent progresses in the field for the formation of CO, HCOOH/HCOO⁻, syngas, and multicarbon products. Unlike previous reports in the field, the other part discussed the key parameters for improving the performances of metal-free N-doped carbon materials for CO₂RR. The roles of N-functionalities in the electrocatalytic activity and selectivity during CO₂RR were also explained. The last section discussed detailed mechanistic aspects and technoeconomic analysis of major products of the CO₂RR over N-doped carbon-based electrocatalysts. Conclusively, some critical questions and insight into designing efficient N-doped carbon materials and also for CO₂RR, including challenges, and knowledge gaps, were provided for better advancement and full fledge of the field toward industrial applications.