Photocatalytic hydrogen production using mesoporous TiO2 doped with Pt

Autor: Patricio J. Valadés-Pelayo, H. de Lasa, Benito Serrano-Rosales, J. F. Guayaquil-Sosa
Rok vydání: 2017
Předmět:
Zdroj: Applied Catalysis B: Environmental. 211:337-348
ISSN: 0926-3373
Popis: A series of mesoporous TiO 2 (meso-TiO 2 ) were synthesized using the sol-gel technique. A Pluronic F127 triblock-copolymer, a structure-directing agent, was incorporated as a soft template into the sol-gel. In addition, and during a separate synthesis, the sol-gel was doped with a Pt precursor. Semiconductors were prepared with 1.00 wt.%, 2.50 wt.%, 5.00 wt.% Pt nominal loadings, respectively. They were calcined at 500 °C and 550 °C following synthesis. Morphological and structural properties were studied by: a) X-ray diffraction, b) UV–vis spectrophotometry, c) N 2 adsorption-desorption (BET, BJH), and d) X-ray photoelectron spectroscopy (XPS). Optical band gap values for meso-TiO 2 and Pt-meso-TiO 2 were calculated by Kubelka-Munk (K-M) function coupled with Tauc plot methodology. It was observed that the prepared semiconductors displayed pore sizes in the 10–40 nm range with bimodal distributions. Their photocatalytic activity for hydrogen production via water splitting was established in a Photo-CREC Water-II reactor under near-UV light irradiation. The aqueous solution contained 2% v/v ethanol, employed as a renewable organic scavenger. The prepared semiconductors showed that the mesoporous 2.50 wt.% Pt-TiO 2 has the highest photoactivity for hydrogen generation. This suggests the important role played by the loading of platinum as a TiO 2 dopant, reducing the optical band gap, increasing electron storage and diminishing, as a result, electron-hole recombination. The measured Quantum Yield (QY), obtained using a rigorous approach, was established for the mesoporous 2.50 wt.% Pt-TiO 2 at a promising level of 22.6%.
Databáze: OpenAIRE
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