A systematic study on the crystal facets-dependent TEA sensing properties of designed anatase {001 and 101} and rutile {110} facets TiO2

Triethylamine (TEA), a toxic and explosive volatile organic compound (VOC) gas, is hazardous to human health and the environment. Therefore, it is crucial to develop crystal-faceted TEA gas sensors with improved sensitivity and rapid detection capabilities. In this study, TiO 2 nanocrystal sensors with different crystal facets of anatase {101} and {001} and rutile {110} were synthesized using the hydrothermal method. The nanomaterials underwent characterization through XRD, SEM, TEM, XPS, and BET analysis. The results revealed that the materials exhibited bipyramid anatase {101} facet, nanorod anatase {001} facet, and rutile {110} facet. The sensors demonstrated superior gas sensing performance in the following order: {101} > {110} > {001} facets to 100 ppm TEA gas at 240 °C. The sensors also exhibited short response and recovery times, low detection limits, excellent stability, repeatability, and selectivity. The enhanced sensing properties of {101} faceted TiO 2 can be ascribed to the bipyramid structure and crystal facets with higher adsorbed oxygen peak specific area, which provide numerous active sites and improved extra oxygen-active site species. This study offers valuable insight into the design mechanism to enhance the TEA response of {101} faceted TiO 2 and further contributes to our understanding of the sensitivity of crystal faceted sensors.