TiO2‐Decorated Graphite Nanoplatelet Nanocomposites for High‐Temperature Sensor Applications

Temperature and/or composition mapping inside high temperature energy conversion and storage devices are challenging, yet of critical importance to improve the material design for optimum performance. Here, the great potential of TiO₂ nanoparticle (NP)‐decorated graphite nanoplatelet (GNP) nanocomposites as high temperature thermal senors or gas sensors is reported. Effects of the GNP substrate on phonon confinement in Raman spectrum, grain growth, and phase stability of anatase TiO₂ NPs at high temperatures are systematically studied. Thermally sensitive Raman signatures, indicating the ultrafast grain growth of TiO₂ NPs in response to short thermal shock treatments (0.1–25 s) at high temperatures, are exploited for high temperature thermal sensing applications. A very high accuracy of nearly 98% in temperature measurements is demonstrated for a given short‐time thermal exposure. Thermal stability of anatase TiO₂ NPs against transformation into the rutile phase in TiO₂‐GNP nancomposites is substantially increased by controlling the surface area of the substrate, which would significantly improve the performance of TiO₂‐based high temperature gas sensors.