Significant Enhancement of Photocatalytic Reduction of CO₂ with H₂O over ZnO by the Formation of Basic Zinc Carbonate

Abstract

Electron-hole pair separation efficiency and adsorption performance of photocatalysts to CO are the two key factors affecting the performance of photocatalytic CO reduction with HO. Distinct from conventional promoter addition, this study proposed a novel approach to address these two issues by tuning the own surface features of semiconductor photocatalyst. Three ZnO samples with different morphologies, surface area, and defect content were fabricated by varying preparation methods, characterized by XRD, TEM, and room-temperature PL spectra, and tested in photoreduction of CO with HO. The results show that the as-prepared porous ZnO nanosheets exhibit a much higher activity for photoreduction of CO with HO when compared to ZnO nanoparticles and nanorods attributed to the existence of more defect sites, that is, zinc and oxygen vacancies. These defects would lower the combination rate of electron-hole pair as well as promote the formation of basic zinc carbonate by Lewis acid-base interaction, which is the active intermediate species for photoreduction of CO. ZnO nanoparticles and ZnO nanorods with few defects show weak adsorption for CO leading to the inferior photocatalytic activities. This work provides new insight on the CO activation under light irradiation.

Progress on Catalyst Development for Direct Synthesis of Dimethyl Carbonate from CO2 and Methanol

“…The Zr-doped material generated a fluorite-like solid solution that enhanced the CO 2 adsorption on the oxygen vacancies to form bidentate coordinated carbonate as an intermediate able to participate in the reaction. The surface oxygen vacant sites served as Lewis acid sites that promoted the CO 2 adsorption [64][65][66]. From this study, the relationship between the surface oxygen vacancies, CO 2 adsorption capacity, and catalyst activity was clearly demonstrated.…”

Plasmonic Hot Electrons from Oxygen Vacancies for Infrared Light‐Driven Catalytic CO2 Reduction on Bi2O3−x

“…Therefore, raising the temperature may have two positive effects on the photocatalytic reactions on Bi 2 O 3− x according to the literature. First, it is beneficial to activate the adsorbed CO 2 and H 2 molecules into excited states according to the Bose‐Einstein distribution, [37] and excite other thermal reaction steps that occur on the catalyst surface, such as the adsorption‐desorption equilibrium of reactants and products, and the diffusion of adsorbed species [38] . Second, by gaining energy from heating, the energy levels for the hot‐electrons excited by the LSPR of Bi 2 O 3− x can be raised further; thus, these electrons are more active than those only excited by light irradiation [37] .…”

Efficient Removal of Organic Dyes and Lead Ions With Eco-friendly Prepared Zinc Oxide Nanoparticles From Water 

“…Among these nanomaterials zinc oxide nanoparticles (ZnO NPs) is considered to be one of the most used nanomaterials. ZnO NPs featured by the purity of their structure and the well-designed composition, large specific surface area and small, hollow, and layered structures, which has been used in different applications, such as corrosion inhibition [2], biomedical [3][4][5][6][7][8], food packaging [9], energy [10], textiles [11], antibacterial [12], water treatment through photocatalytic process [13,14], CO2 conversion [15,16], and adsorption of organic [17], and inorganic pollutants [18].…”