Thermo-photo production of hydrogen using ternary Pt-CeO2-TiO2 catalysts: A spectroscopic and mechanistic study

Authors are thankful to “Ministerio de Ciencia, Innovaci´on y Universidades” (Spain) for supporting the work carried out through the PID2019-105490RB-C31 grant. ESRF (BM23 beamline) synchrotron and staff (Drs. G. Agostini and O. Mathon) are also thanked for the provision of beamtime as well as the supply of reference materials/spectra. The support by CONACyT, Mexico (SENER-CONACyT 117373) is also acknowledged by U. C.-F. I. B.-N. thanks MINECO for a FPI doctoral fellowship (BES-2017-080069). MF-G acknowledges Prof. F. Fern´andez- Martín for fruitful discussions.The gas phase thermo-photo production of hydrogen from methanol:water mixtures was tested using platinum ceria-titania ternary solids. This contribution focusses on the analysis of the role of ceria and the usefulness of combining heat and light sources in order to boost catalytic activity. To this end, we provide a quantitative assessment of thermo-photo activity as well as a detailed characterization of the catalytic solids with emphasis in the use of in-situ X-ray absorption and infrared spectroscopies. The adequate combination of components in the platinum ceria-titania ternary system renders highly active and stable catalysts, maximizing hydrogen production (rate of ca. 45 mmol g-1h−1) for a solid having a 1/2.5 wt% of platinum/ceria supported on titania. The characterization shows that this occurs through a synergetic effect among components of the solids and takes place with a critical role of defects located at the ceria-titania interface and the noble metal component. The cooperative action between components promotes the evolution of specific carbon-containing intermediates (related to the step-wise hole-triggered oxidation of the methanol molecule, decarbonylation of intermediates and the water gas shift) and the concomitant production of hydrogen.“Ministerio de Ciencia, Innovación y Universidades” (Spain) (PID2019-105490RB-C31 grant. ESRF (BM23 beamline)CONACyT, Mexico (SENER-CONACyT 117373)MINECO (BES-2017-080069