Wet photochemical filling: a new low-diameter tube-filling method based on differentiated nanotube surfaces

Abstract

In this work, by using a simple chemical morphology freezing method novel low-diameter tubular nanocomposites (TiO₂–NTs@SiO₂) with differentiated surfaces are prepared, in which the TiO₂ layer acts as a photoactive inner surface and the SiO₂ layer acts as an insulating outer surface. Because of the photoactivity of TiO₂, under UV light irradiation, only the inner TiO₂ surface can photoreduce a H₂PtCl₆ precursor solution to Pt nanoparticles on its surface. As a result, Pt nanoparticles are highly selectively filled in the tube inner channel after this wet photochemical filling process. Due to the high dispersity of Pt nanoparticles in the channel, the method can improve catalytic activity efficiently by increasing the ultimate effective Pt load. In photocatalytic H₂-production experiments, nanotubes filled with 6 wt% Pt show the highest photoactivity of all the samples; this activity is twice that obtained with TiO₂ nanoparticles loaded with 0.6 wt% Pt.