Growth of TiO2 nanostructures exposed {001} and {110} facets on SiC ultrafine fibers for enhanced gas sensing performance

In situ detection of toxic and combustible gases in harsh environments is much more desired in the fields of aerospace and chemical industries, etc. Herein, we have successfully grown {001} facets-exposed TiO2 nanosheets (TNS001) and {110} facets-exposed TiO2 nanorods (TNR110) on the surface of macro-meso-microporous SiC fibers (MMM-SFs). The received hierarchical TNS001@MMM-SFs sensor possesses a core-shell hierarchical structure, and exhibits a high response of 19.2 at the temperature of 450 °C towards acetone, which is 1.2 and 1.8 times as high as those of TNR110@MMM-SFs and bare TNS001, respectively. Besides, the TNS001@MMM-SFs also present good stability, fascinating selectivity and low response time to acetone. This excellent gas detecting ability is mainly contributed to the exposing of high-energy {001} crystal facets of TiO2 and the synergetic effect of TiO2/SiC heterojunctions as well as the core-shell hierarchical architectures. This work gives a general strategy of exposing high-index energy facet combined with constructing hierarchical heterojunctions structure to fabricate gas sensors.