Preparation of Pd nanoparticles modified hollow TiO2 dodecahedrons for highly selective hydrogen detection

It is important to develop hydrogen gas sensors with low power consumption, rapid response and high sensitivity/selectivity to monitor hydrogen leakage. Here, TiO 2 hollow dodecahedrons are successfully synthesized using ammonium tungsten phosphate hydrate dodecahedrons as hard templates. Then, Pd/TiO 2 hollow dodecahedral composites are prepared by loading Pd nanoparticles onto TiO 2 hollow dodecahedrons by liquid phase reduction method. Both TiO 2 and Pd/TiO 2 hollow dodecahedrons are fabricated into gas sensors, and their sensing performance is evaluated. The results show that the Pd/TiO 2 hollow dodecahedral sensor exhibits a highly sensitive response (3.5) to 200 ppm hydrogen at a low working temperature of 100 °C. In addition, the Pd/TiO 2 hollow dodecahedrons also show a short response/recovery time (19 s/5.5 s), a good linear relationship (R 2 =0.995), good repeatability and excellent stability for hydrogen detection. The excellent gas sensing performance of the Pd/TiO 2 hollow dodecahedrons is attributed to their hollow structure and the catalytic sensitization of Pd nanoparticles. This work demonstrates that a new preparation route of sensing material for highly selective and selective hydrogen detection.