Nanomaterials and hybrid nanocomposites for CO 2 capture and utilization: environmental and energy sustainability.

Anthropogenic carbon dioxide (CO 2 ) emissions have dramatically increased since the industrial revolution, building up in the atmosphere and causing global warming. Sustainable CO 2 capture, utilization, and storage (CCUS) techniques are required, and materials and technologies for CO 2 capture, conversion, and utilization are of interest. Different CCUS methods such as adsorption, absorption, biochemical, and membrane methods are being developed. Besides, there has been a good advancement in CO 2 conversion into viable products, such as photoreduction of CO 2 using sunlight into hydrocarbon fuels, including methane and methanol, which is a promising method to use CO 2 as fuel feedstock using the advantages of solar energy. There are several methods and various materials used for CO 2 conversion. Also, efficient nanostructured catalysts are used for CO 2 photoreduction. This review discusses the sources of CO 2 emission, the strategies for minimizing CO 2 emissions, and CO 2 sequestration. In addition, the review highlights the technologies for CO 2 capture, separation, and storage. Two categories, non-conversion utilization (direct use) of CO 2 and conversion of CO 2 to chemicals and energy products, are used to classify different forms of CO 2 utilization. Direct utilization of CO 2 includes enhanced oil and gas recovery, welding, foaming, and propellants, and the use of supercritical CO 2 as a solvent. The conversion of CO 2 into chemicals and energy products via chemical processes and photosynthesis is a promising way to reduce CO 2 emissions and generate more economically valuable chemicals. Different catalytic systems, such as inorganics, organics, biological, and hybrid systems, are provided. Lastly, a summary and perspectives on this emerging research field are presented.