Study of photocatalytic 2-propanol dehydrogenation for solar thermal cell

A solar thermal cell converts low temperature solar thermal energy into electric power. It consists of chemical reactions of 2-propanol dehydrogenation and acetone hydrogenation, and a fuel cell. In this study, we studied photocatalytic 2-propanol dehydrogenation in order to apply directly sunlight to solar thermal cell. We report the results of 2-propanol dehydrogenation when noble metal (Pt, Ru, Rh and Pd) supported on TiO₂ was used as a catalyst (designated hereafter as metal/TiO₂). A metal loading ratio was 5 wt%. Three kinds of TiO₂ (Ishihara sangyo kaisha. LTD:ST-O1, ST-21 and ST-31) were used in this study. The particle size of ST-O1, ST-21 and ST-31 was 7, 20 and 7 μm, respectively. The specific surface area of ST-O1, ST-21 and ST-31 was 321, 60.9 and 275 m²/g, respectively. We examined the activity of various combinations of noble metal and TiO₂ for the reaction and it is revealed that Pt/ST-O1 has the highest activity. Compared with 2-propanol dehydrogenation with noble metal supported on activated carbon, which is not photoreaction, the characteristics of photocatalytic 2-propanol dehydrogenation with metal/TiO₂ are summarized in small acetone retardation, large reaction rate under nonboiling condition and large reaction rate under high acetone concentration