PhD candidate, Western University
My PhD research is related to the photocatalytic hydrogen production through water dissociation. Hydrogen is an environmentally friendly energy vector, of great interest for the society to overcome in the near future with the energy world’s demand. Thus, I am focused on the synthesis of novel mesoporous semiconductor materials that can be activated by Ultraviolet and/or visible light. Whit this end, a novel bench scale photo reactor (Photo-CREC-water-II) with good mixing and uniform light distribution is applied to carry out the photocatalytic hydrogen production via water-splitting. Hence, during the first four years of my PhD, I successfully prepared Pt on mesoporous TiO2 semiconductors and carried out fruitful experiments for photocatalytic hydrogen formation via water splitting. All these results are of great technical value for environmentally friendly and sustainable hydrogen production. Additionally, I also studied metal loading of the photocatalyst on the support, photocatalyst loading and evaluated the radiation in the Photo-CREC-water-II for the calculation of photonic efficiencies. The final stage of my PhD is to report the results I have got so far to the scientific community publishing them in an International Chemical Engineering/Environmental journal.
Abstract: A series of mesoporous TiO2 (meso-TiO2) 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) N2 adsorption-desorption (BET, BJH), and d) X-ray photoelectron spectroscopy (XPS). Optical band gap values for meso-TiO2 and Pt-meso-TiO2 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 to 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-TiO2 has the highest photoactivity for hydrogen generation. This suggests the important role played by the loading of platinum as a TiO2 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-TiO2 at a promising level of 22.6%.
Pub.: 13 Apr '17, Pinned: 29 Aug '17