CeO₂ Nanostructures Enriched with Oxygen Vacancies for Photocatalytic CO₂ Reduction

Abstract

Synthesizing nanomaterials at the expense of solar energy and the associated energy generation have utmost significance as far as environmental sustainability is concerned. Here, sunlight-assisted combustion synthesis of a nanoscale metal oxide (CeO2) is reported. The sunlight, as a clean renewable energy source, is used for the first time to initiate the exothermic combustion reaction and to introduce oxygen vacancies into the CeO2. The current synthesis setup controls the environmental problems of gas evolution, usually associated with the conventional method, and thus maintains the green pathway. Additionally, for comparison, CeO2 nanoparticles are also synthesized using the conventional solution combustion method (CeO2-CSC). It is found that the CeO2 synthesized using sunlight-assisted combustion (CeO2-SAC) possesses a smaller particle size, a higher concentration of oxygen vacancies, and a narrower band gap than the CeO2-CSC. Therefore, CeO2-SAC demonstrates higher photocatalytic performance in converting CO2 to CH3OH (0.702 μmol h–1 g–1) than the CeO2-CSC (0.397 μmol h–1 g–1), thus pointing toward environmentally benign photocatalytic CO2 reduction.

Highly Active PdO/Mn3O4/CeO2 Nanocomposites Supported on One Dimensional Halloysite Nanotubes for Photoassisted Thermal Catalytic Methane Combustion

“…The electron paramagnetic resonance (EPR) signals with a g factor of 2.003 should be attributed to Ce 3+ (Figure 3 d,e). It can be seen that the intensity of the Ce 3+ signals increased significantly under irradiation or by increasing temperature, also suggesting the presence of a higher concentration of oxygen vacancies [13a, 23b] . This further proves that visible light irradiation is beneficial for adsorption and activation of O 2 .…”

Impacts of the Catalyst Structures on CO2 Activation on Catalyst Surfaces

“…The ability of metal oxides to bind and activate CO 2 depends greatly on several factors, including their preparation methods, physiochemical properties, redox properties, and electronic and geometric structures [108,114,118]. The preparation methods were found to impact the properties of CeO 2 nanostructures for the photocatalytic reduction of CO 2 [119]. A high surface area was obtained for catalysts synthesized through the sunlight-assisted combustion process, in addition to possessing a small particle size, high concentration of oxygen vacancies, and a narrow bandgap.…”

Photocatalytic degradation of organic pollutants using Trianthema Portulastrum leaf extract based CeO2 nanoparticles

“…The various quantities of oxygen vacancies show that photocatalytic results are different. It further suggests that significantly more oxygen vacancies will require quick recombination of electron holes and thus decrease photocatalysis for Chemical CO2-Nps [ 45 ]. The difference in photocatalytic activity has highly been linked in accordance with concentration errors on the nanoparticles surface [ 45 ].…”

“…It further suggests that significantly more oxygen vacancies will require quick recombination of electron holes and thus decrease photocatalysis for Chemical CO2-Nps [ 45 ]. The difference in photocatalytic activity has highly been linked in accordance with concentration errors on the nanoparticles surface [ 45 ]. They also showed that surface defects have been increased as the particle sizes decreased and photocatalytic activity increased.…”