Stabilizing 3 nm-Pt nanoparticles in close proximity on rutile nanorods-decorated-TiO2 nanofibers by improving support uniformity for catalytic reactions

One of the most urgent concerns for supported catalysts is to enhance their thermal stability against sintering upon high temperatures (above 300 degrees C). In this work, we decorated the rough surface of TiO2 nanofibers with a sheath of rutile nanorods to improve their surface uniformity and explored them as new reliable substrates to stabilize Pt nanoparticles without capping shell. During preparation, the surface-initiated grain growth facilitates the decorated TiO2 crystals to transform into rutile nanorods, exposing rutile {111} and {110} facets. With the presence of TiO2 nanofibers, these rutile nanorods were finely confined against coalescence and reconstruction upon 700 degrees C, offering reliable supports for stabilizing metal nanoparticles. Therefore, the diminished driving force for sintering enables the whole catalyst system to withstand temperatures up to 500 degrees C at an oxidative atmosphere. After calcination at 500 degrees C, the Pt on rutile nanorods-decorated-TiO2 nanofibers exhibited nearly 3times higher reaction rate constant (27.8 s(-1).g(-1).L-1) toward hydrogenation of 4-nitrophenol over those on unmodified TiO2. Moreover, such a thermally stable catalyst was active for the oxidation of soot particulates, decreasing the conversion temperature and maintaining a small Pt size of 6.99 nm after the sinter-promoting exothermic oxidation.