Nitrogen-doped metal-free carbon catalysts for (electro)chemical CO2 conversion and valorisation

Abstract

Carbon dioxide (CO₂) is regarded as the main contributor to the greenhouse effect. As a potential strategy to mitigate its negative impacts, the reduction of CO₂ is environmentally critical, economically meaningful and scientifically challenging. Concerns regarding anthropogenic emissions have recently sparked interest in the CO₂ chemical transformation techniques. Being both thermodynamically and kinetically unfavorable, CO₂ conversion generally requires efficient metal-based catalysts although they have multiple competitive disadvantages such as high costs, low availability and detrimental effects on the environment. A new class of catalysts based on earth-abundant carbon materials has been considered as an efficient, low-cost, metal-free alternative for both the capture and catalytic or electrocatalytic conversion of CO₂. CO₂ electrochemical reduction (CO₂RR) offers a new and important pathway towards renewable energy storage and production of fuels, and CO₂ cycloaddition with epoxides to cyclic or polymeric carbonates opens up new prospects for the production of polymers and fine chemicals. This review provides an overview of the progresses made in nitrogen-doped metal-free carbon catalysts for CO₂ electrochemical conversion and CO₂ conversion into cyclic carbonates into useful fuels and chemicals with a focus on the results underlying their mechanistic behavior, advantages and/or limitations of this metal-free N-doped carbon catalysts on CO₂ conversion and valorisation.