Impacts of the Catalyst Structures on CO2 Activation on Catalyst Surfaces

Utilizing CO₂ as a sustainable carbon source to form valuable products requires activating it by active sites on catalyst surfaces. These active sites are usually in or below the nanometer scale. Some metals and metal oxides can catalyze the CO₂ transformation reactions. On metal oxide-based catalysts, CO₂ transformations are promoted significantly in the presence of surface oxygen vacancies or surface defect sites. Electrons transferable to the neutral CO₂ molecule can be enriched on oxygen vacancies, which can also act as CO₂ adsorption sites. CO₂ activation is also possible without necessarily transferring electrons by tailoring catalytic sites that promote interactions at an appropriate energy level alignment of the catalyst and CO₂ molecule. This review discusses CO₂ activation on various catalysts, particularly the impacts of various structural factors, such as oxygen vacancies, on CO₂ activation.