A photocatalytic transformation realized by Pd/TiO2 particle size modulation: from oxidative dehydrogenation of ethane to direct dehydrogenation of ethane

Abstract Transformation from photocatalytic oxidative dehydrogenation of ethane (PODHE) to photocatalytic dehydrogenation of ethane (PDHE) is an attractive process. A series of Pd/TiO2 photocatalysts with different Pd loading amount were synthesized by photochemical deposition. And the Pd particle sizes varied from 1 nm to 4 nm. PDHE happened instead of POHDE over Pd particles smaller than 3 nm. The best PDHE performance (H2, 799.4; C2H4, 614.9, in micromoles per gram of catalyst) was obtained over 0.5 wt.% Pd/TiO2 catalyst. And it was 3 times of it of PODHE over 1 wt.% Pd/TiO2. Reducing the Pd particle size of Pd/TiO2 would increase Pd0/Pd2+ and lower the valence band and conductive band of Pd/TiO2, which affect the catalytic behaviors. Detailed formation of products was investigated in this work.