Nanomaterials and hybrid nanocomposites for CO2 capture and utilization: environmental and energy sustainability

Anthropogenic carbon dioxide (CO2) emissions have dramatically increased since the industrial revolution, building up in the atmosphere and causing global warming. Sustainable CO2 capture, utilization, and storage (CCUS) techniques are required, and materials and technologies for CO2 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 CO2 conversion into viable products, such as photoreduction of CO2 using sunlight into hydrocarbon fuels, including methane and methanol, which is a promising method to use CO2 as fuel feedstock using the advantages of solar energy. There are several methods and various materials used for CO2 conversion. Also, efficient nanostructured catalysts are used for CO2 photoreduction. This review discusses the sources of CO2 emission, the strategies for minimizing CO2 emissions, and CO2 sequestration. In addition, the review highlights the technologies for CO2 capture, separation, and storage. Two categories, non-conversion utilization (direct use) of CO2 and conversion of CO2 to chemicals and energy products, are used to classify different forms of CO2 utilization. Direct utilization of CO2 includes enhanced oil and gas recovery, welding, foaming, and propellants, and the use of supercritical CO2 as a solvent. The conversion of CO2 into chemicals and energy products via chemical processes and photosynthesis is a promising way to reduce CO2 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.