CO₂ conversion into fuels and value-added chemicals: from molten salt catalysts to metal–organic and covalent–organic frameworks

The increase in the concentration of carbon dioxide (CO₂) in the earth’s atmosphere is one of the major environmental challenges of our time, playing a significant role in climate change. The conversion of CO₂ into valuable fuels and chemicals is a promising approach to mitigate the impact of this greenhouse gas and utilize it as a renewable carbon source. This article reviews various CO₂ conversion routes, including reverse water gas shift (RWGS), methanol synthesis, conversion to olefins, dimethyl ether (DME), and formic acid, and analyzes their thermodynamic and selectivity aspects. Next, the role of molten salt catalysts in CO₂ activation is reviewed, with a focus on their physicochemical properties and the roles of anions and cations. Also, metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) are introduced as novel catalytic substrates for CO₂ reduction, hydrogenation, and photoconversion. Mechanistic studies, hybrid systems (such as combining MOFs with quantum dots or metal nanoparticles), and electric field effects and surface phenomena in plasmonic substrates are also reviewed. Finally, current challenges, technical and research limitations, and future perspectives on the development of CO₂ conversion technologies are presented.