Photonic efficiency and mechanism of photocatalytic molecular hydrogen production over platinized titanium dioxide from aqueous methanol solutions

The photocatalytic molecular hydrogen (H2) production from aqueous methanol solutions over Pt-loaded commercial (Evonik Aeroxide TiO2 P25 and Sachtleben Hombikat UV100) and home made (TiO2 P25HT) titanium dioxide photocatalysts has been studied. The photonic efficiencies were calculated by dividing the H2 production rate by the photon flux. The effect of the employed light intensity on the H2 production rate was investigated. The products of the photocatalytic methanol oxidation were quantitatively analyzed employing different test conditions, i.e., different illumination times, pH values, and methanol concentrations. The balance between the amount of evolved H2 and the amount of photocatalytic methanol oxidation products was checked. Based on the obtained results, the difference in the photocatalytic activities between the investigated photocatalysts, the effect of the employed light intensities, and the description of the photocatalytic H2 production from aqueous methanol solutions is discussed.