Zhuoying Zeng

With the continuous emission of greenhouse gases, the rational transformation and utilization of CO2 is particularly important. Cyclic carbonates are a kind of versatile compounds and have wide applications in Li-ion batteries, pharmaceutical manufacturing and many fine chemicals. Cycloaddition of CO2 and epoxide to synthesize cyclic carbonates is considered one of the most promising CO2 conversion routes because of its 100% atomic economy, non-toxicity, as well as a more economic technical route for the utilization of CO2. In this paper, this review surveys the synthesis of cyclic carbonates employing CO2 as a building block. The mechanisms of CO2 activation have been described in detail due to the thermodynamic stability of CO2 molecule. The reaction mechanism of CO2 and epoxide is expounded, and seven CO2 activation methods are summarized and compared, deeply analyzing the research progress of recent years. To reduce the activation energy of the CO2 conversion, the utilization of catalysts is very crucial. Various types of catalysts suitable for the synthesis of cyclic carbonates derived from CO2 have been expounded in depth. Finally, the development trend of catalysts is prospected. The development of improved catalysts is strongly demanded for successful commercialization of CO2 transformation technologies. This review enables researchers to timely seize the current advancements and thus may provide some rewarding insights for future investigations on the synthesis of cyclic carbonates employing CO2 as the feedstock. It will provide a good reference and guide for scholars to achieve the better improvements.

Abstract Owing to the structural stability, modifiable acidity, and abundant pores/channels, zeolite‐based materials can act as catalysts or supports for effective conversion of volatile organic compounds (VOCs). In this review, a series of VOC oxidation processes catalyzed by zeolite‐based materials will be introduced, which include thermal oxidation, photocatalytic degradation, plasma‐driven removal, catalytic ozonation, microwave‐assisted degradation, and hybrid systems, where the specific roles, modification strategies, and structure–performance relationships of zeolites are discussed in depth. The following topics will also be covered, including the catalytic mechanisms of VOC oxidation, types of zeolite‐based materials in VOC catalytic oxidation, operation parameters in the processes, and reactor designs for efficiency optimization and cost control.

Abstract Three processes are covered in this work for the catalytic CO 2 conversion and H 2 /syngas production, namely thermal catalysis, plasma‐assisted catalysis, and membrane‐assisted catalysis. In the thermal catalysis, four catalyst modification strategies (size control, interface engineering, surface regulation, and oxygen species) are critically illustrated by referring the structure–performance relationships, reaction pathways (molecule activation and intermediate transformation), and catalyst deactivation (coking, sintering, and poisoning). In the plasma‐ and membrane‐assisted catalytic processes, the synergy of catalyst‐plasma and catalyst‐membrane is respectively discussed based on the reaction category (plasma‐assisted decomposition, plasma‐assisted reforming, and plasma‐assisted CO 2 reduction) and gas to be permeated (membranes for H 2 , O 2 , CO 2, and H 2 O separation). In summary, to ensure a highly efficient and stable catalytic process for CO 2 transformation into value‐added products and selective production of H 2 and syngas, a smart design of catalysts is necessary, which are expected to possess a small size and high dispersion, multifunctional metal–metal or metal–support interfaces, balanced surface acidity and basicity, abundant oxygen species, and fast oxygen mobility. To further enhance the conversion rate, yield, selectivity, catalyst robustness, energy efficiency, and operation cost‐effectiveness, a synergistic combination of catalysts with plasma or membrane would be favorable mainly due to the extra high‐energy species generated in plasma and high chemical gradient at both sides of membrane.