Single crystalline brookite titanium dioxide nanorod arrays rooted on ceramic monoliths: a hybrid nanocatalyst support with ultra-high surface area and thermal stability

Abstract

In this study, a cost-effective solution synthesis of commercial scale single crystalline titanium dioxide (TiO₂) nanorod arrays has been successfully achieved on the inner walls of cordierite monoliths, which may provide a new class of nanostructured hybrid support for catalysis and energy applications. The morphological evolution has been observed from dandelion TiO₂ nanorod clusters to vertically aligned nanorod arrays while increasing the solution treatment time. A heterogeneous nucleation–dissolution–crystallization mechanism is proposed for the growth of the brookite structured TiO₂ nanorod arrays on the inner walls of honeycomb monoliths. The brookite structured TiO₂ nanorod arrays have a high surface area up to ~250 m² g⁻¹, with an overall specific surface area in the hybrid nanostructured monolith increasing by 1.8 and 2.5 times after TiO₂ nanorods coating for 4 h and 24 h, respectively. The thermal stability tests using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and hydrothermal stability tests under boiling water for 24 h suggest that the TiO₂ nanorods coated hybrid monoliths are very stable. An as-prepared 9-cm-long TiO₂ nanorod-array monolithic device was demonstrated as a continuous flow fixed-bed absorbent with efficient performance in Rhodamine B removal from aqueous solution.