Wavelength-Dependent Activity of Oxygen Species in Propane Conversion on Rutile TiO 2 (110).

Photocatalytic oxidative dehydrogenation of propane (C 3 H 8 ) into propene (C 3 H 6 ) under mild conditions holds great potential in the chemical industry, but understanding how active species participate in C 3 H 8 conversion remains a significant challenge. Here, the wavelength-dependent activities of bridging oxygen (O b 2- ) and the Ti 5c -bound oxygen adatom (O Ti 2- ) of model rutile (R) TiO 2 (110) in C 3 H 8 conversion have been investigated. Under 257 and 343 nm irradiation, hole-trapped O Ti - and O b - can abstract the hydrogen atom of C 3 H 8 , forming the CH 3 CH • CH 3 radical and C 3 H 6 . However, the rate of C 3 H 8 conversion with hole-trapped O b - is strongly dependent on the wavelength, primarily producing the C 3 H 7 • radical. In the case of hole-trapped O Ti - , C 3 H 6 is the main product, which is nearly independent of wavelength. The differences in the wavelength-dependent activity and product selectivity are likely due to dynamic control rather than thermodynamic control. The result provides a deeper understanding of the dynamic processes involved in the conversion of light alkanes in TiO 2 photocatalysis.