Nanomaterials as catalysts for CO2 transformation into value-added products: A review

Carbon dioxide (CO 2) is the most important greenhouse gas (GHG), accounting for 76% of all GHG emissions. The atmospheric CO 2 concentration has increased from 280 ppm in the pre-industrial era to about 418 ppm, and is projected to reach 570 ppm by the end of the 21 st century. In addition to reducing CO 2 emissions from anthropogenic activities, strategies to adequately address climate change must include CO 2 capture. To promote circular economy, captured CO 2 should be converted to value-added materials such as fuels and other chemical feedstock . Due to their tunable chemistry (which allows them to be selective) and high surface area (which allows them to be efficient), engineered nanomaterials are promising for CO 2 capturing and/or transformation. This work critically reviewed the application of nanomaterials for the transformation of CO 2 into various fuels, like formic acid , carbon monoxide , methanol, and ethanol. We discussed the literature on the use of metal-based nanomaterials, inorganic/organic nanocomposites, as well as other routes suitable for CO 2 conversion such as the electrochemical, non-thermal plasma, and hydrogenation routes. The characteristics, steps, mechanisms, and challenges associated with the different transformation technologies were also discussed. Finally, we presented a section on the outlook of the field, which includes recommendations for how to continue to advance the use of nanotechnology for conversion of CO 2 to fuels.