MOF derived carbon modified porous TiO2 mixed-phase junction with efficient visible-light photocatalysis for cyclohexane oxidation

In this paper, carbon modified porous TiO 2 mixed-phase junction was successfully fabricated by using the MIL-125(Ti)-P25 composite as the precursor. The porous TiO 2 possessed abundant pores and large surface area inherited from its precursor during a simple one-step pyrolysis in a crucible, and the modified TiO 2 showed catalytic activity for photocatalytic cyclohexane oxidation. Moreover, the ratios of anatase/rutile TiO 2 and carbon contents in the modified TiO 2 mixed-phase junction can be regulated conveniently. Among the mixed-phase porous TiO 2 , the C TiO 2 –4 sample containing 12.4 wt% rutile TiO 2 presented the best photocatalytic activity, which was also much better than those of carbon modified pure anatase or rutile TiO 2 . The carbon modification was characterized by carbon doping and surface carbon species, which played the vital role in enhancing the photocatalytic activity of the mixed-phase TiO 2 . Carbon doping into TiO 2 lattice can effectively reduce its band gap energy and extend the light response range. The carbon species on the TiO 2 surface can improve the light absorption efficiency and promote the transport of photogenerated electrons. Free radicals capture experiments demonstrated that •OH and •O 2 − radicals were important active species in the cyclohexane oxidation reaction. This work provides a MOF-mediated P25-assisted synthesis strategy that may guide the design of other photocatalysts.