Carbon nanotube embedded mesoporous titania pore-hole inorganic hybrid materials with high thermal stability, improved crystallinity and visible-light driven photocatalytic performance

Abstract Pore-hole inorganic hybrid materials: carbon nanotube (CNT)-embedded mesoporous titania (MT) (CNMT) were controlled fabricated in supercritical conditions by deposition of titanium sol containing a liquid crystal template. The as-prepared hybrid materials were characterized by using modern analytical tools. Experimental results indicate that the MT in hybrid materials maintained mesoporous structure up to 600 °C. This result may be attributed to the structure of CNTs embedded in the anatase matrix. Embedding of CNTs in the nanophase titania matrix helped protect the mesoporous framework against collapsing, inhibited undesirable grain growth, suppressed transformation of anatase into rutile, and increased the thermal stability of MT during calcination. A possible mechanism for the formation of highly thermostable MT in the hybrid materials is also proposed. Such formation could be further confirmed by transmission electron microscopy and X-ray photoelectron spectroscopy. Calcination temperature greatly influenced embedding effect of CNTs on the microstructure of MT in hybrid materials. The maximum phenol degradation (99% after 140 min) is observed for CNMT-500 samples. It is attributed to the well mesostructure, which facilitates mass transport, the large surface area that offers more active sites and hydroxyl radicals, and perfect crystallinity that favors the separation of photogenerated electron–hole pairs, confirmed by photoluminescence emission spectrum.