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, TiO2 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 degrees 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 TiO2 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 TiO2 and further contributes to our understanding of the sensitivity of crystal faceted sensors.