Solar photocatalytic H2 production over CeO2-based catalysts: Influence of chemical and structural modifications

• Published in: Catalysis today 2021-11, Vol.380, p.187-198
• Main Authors: Fiorenza, Roberto, Balsamo, Stefano Andrea, Condorelli, Marcello, D’Urso, Luisa, Compagnini, Giuseppe, Scirè, Salvatore
• Format: Article
• Language: English
• Subjects: CeO2 composites; Cerium oxide; H2 production; Laser treatments; Photocatalysis
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2021.02.003

[Display omitted] •The best sample was the chemically modified laser treated CeO2-WO3 composite.•An efficient charge carriers separation occurred with the laser treated CeO2-WO3.•The chemical and structural changes due to the WO3 and laser gave a defective CeO2.•Different photocatalytic mechanisms were related to the modifications of CeO2. Different CeO2-based materials employed as unconventional photocatalysts for H2 production were here examined. The performances of bare CeO2 prepared by precipitation were compared with those of CeO2-WO3 composites synthetized by co-precipitation and surfactants-mediated precipitation. The bare CeO2 and the best CeO2-WO3 composite were treated with laser irradiation to investigate the modifications of cerium oxide due to this process. Considering the photocatalytic performance, the CeO2-WO3 composite prepared with the HMTA (hexamethylenetetramine) surfactant and irradiated with laser increased the H2 production up to 4 times compared to the bare CeO2, whereas the laser-modified CeO2 and the CeO2-WO3 synthetized by co-precipitation led to a smaller increase of H2 evolution (1.4 and 1.2 times higher than the as-prepared CeO2, respectively). On the basis of the characterization data (Raman, UV–vis Diffuse Reflectance, Photoluminescence, X-ray photoelectron spectroscopies, Transmission electron microscopy and N2 physisorption measurements) it was established that the addition of the HMTA gave higher WO3 dispersion, whereas the subsequent laser treatment facilitated the progressive incorporation of WO3 into CeO2, resulting in a more efficient doping process and a more defective CeO2. All these features were beneficial for the photoproduction of hydrogen. The tuning and the combination of the chemical and the structural modifications of ceria can be a promising route for the solar-driven photocatalysts designed for the green production of H2.