Chemical fixation of CO₂ into useful organic compounds has been attracting much attention from the viewpoint of CO₂ emission reduction and energy structure reformation. A useful and widely investigated chemical utilization of CO₂ is the cycloaddition of CO₂ to epoxides for the synthesis of cyclic carbonates. Efforts have been paid to the design and preparation of various catalyst systems that are active and selective to the production of the desired products under mild conditions and in green processes. This article is to review the current state of the catalyst development and the experimental and theoretical analysis of reaction mechanism for the cyclic carbonate synthesis from epoxides, one of currently important reactions involving CO₂ as a reactant with 100% atom economy. Particular attention is given to the catalysis of multifunctional catalyst systems such as metal- and hydrogen-bond donor (HBD)-based catalysts.

Novel environmentally benign urea derivative-based ILs were successfully prepared and characterized, and displayed exceptional performances for both CO₂ capture and CO₂ catalytic conversion under metal-, cocatalyst- and solvent-free conditions.

The Ag₂O–g-C₃N₄ composite was prepared by the coprecipitation method and was well characterized by X-ray diffraction, transmission electron microscopy with energy dispersion X-ray spectroscopy, UV-vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, photoluminescence spectroscopy and surface photovoltage spectroscopy. The photocatalytic activities were evaluated in the degradation of Rhodamine B aqueous solution. The results showed that Ag₂O sized 5–10 nm was highly anchored on the surface of the pure g-C₃N₄ support, causing the Ag₂O–g-C₃N₄ composite to show stronger absorption in the visible light region and higher photocatalytic activities than pure g-C₃N₄ and Ag₂O. The enhanced photocatalytic activities were attributed to combined effects, including highly dispersed smaller Ag₂O particles, stronger visible absorption and higher charge separation efficiency. The possible mechanism for the photocatalytic activity of Ag₂O–g-C₃N₄ was tentatively proposed.

The dominant role of the magnetoresistance effect caused by spin electron scattering in the oxygen evolution reaction is unveiled through an in situ tunable magnetic field-electrochemical testing system.