Acetaldehyde degradation under UV and visible irradiation using CeO2–TiO2 composite systems: Evaluation of the photocatalytic efficiencies

• CeO2–TiO2 materials were prepared by a single-pot microemulsion procedure.
• Optimum performance achieved with a 2.5 M% loading of Ce.
• Efficiency parameters demonstrates the improvement of activity with respect to titania.
• CeO2–TiO2 materials appears as an optimum choice for solar light profiting.

The photocatalytic activity under UV and visible irradiation of a series of CeO2–TiO2 composite materials prepared by microemulsion and subsequently calcined at 500 °C was evaluated using acetaldehyde as a model pollutant. The activities of three composite catalysts containing 2.5, 5 and 25 M% of ceria, as well as a nano-titania reference are compared by means of efficiency parameters; the quantum (or true) efficiency, as well as the photonic (or apparent) efficiency were evaluated. To this end, the lamp emission properties, as well as the radiation field interaction with the catalyst inside the reactor were modeled and numerically calculated. For the evaluation of the radiation absorbed by the catalysts, the optical properties of the materials were measured and a radiative transfer model that considers all potential optical events was built up. The stability of the systems under reaction conditions was also studied. Overall, the results evidence that the composite containing 2.5 Ce mol% outperforms titania by a factor of at least 2, irrespective of the illumination source used in the experiment. This shows the potential of the CeO2–TiO2 composites, a highly active and stable system, for sunlight optimum profiting.

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