REQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal.
Dalton Trans. 2019 Sep 17;48(36):13508-13528. doi: 10.1039/c9dt01691k.
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.
二氧化碳（CO2）被认为是温室效应的主要贡献者。为了减轻其负面影响，减少 CO2 的排放具有重要的环境意义、经济意义和科学挑战性。最近，人们对人为排放的关注引发了对 CO2 化学转化技术的兴趣。CO2 的转化通常需要高效的金属基催化剂，因为 CO2 的转化在热力学和动力学上都不利，但这些催化剂存在成本高、可用性低以及对环境有害等多种竞争劣势。基于丰富的碳材料的新型催化剂被认为是一种高效、低成本、无金属的替代品，可用于捕获和催化或电催化转化 CO2。CO2 电化学还原（CO2RR）为可再生能源的存储和燃料的生产提供了一条新的重要途径，而 CO2 与环氧化物的环加成则为聚合物和精细化学品的生产开辟了新的前景。本综述概述了氮掺杂无金属碳催化剂在 CO2 电化学转化和 CO2 转化为环状碳酸盐以生产有用燃料和化学品方面的进展，重点介绍了这些无金属 N 掺杂碳催化剂在 CO2 转化和增值方面的机理行为、优势和/或局限性的研究结果。
