Raman and MASNMR studies to support the mechanism of low temperature hydrogen sensing by Pd doped mesoporous SnO2

Tin dioxide nanoparticles synthesized by low temperature hydrothermal route, incorporated with Pd have shown to be very efficient in the sensing of hydrogen gas at very low temperatures. The morphology of the synthesized nanoparticles was determined by XRD and TEM. The gas sensing studies optimized the operating temperature and composition of Pd to obtain a highly efficient material for hydrogen sensing. 0.5 wt% Pd in SnO2 showed a fast response (less than 10 s) to hydrogen at an operating temperature of 50 °C. The present paper details an insight into sensing mechanism based on the trends from Raman and MASNMR studies. These studies establish and support sensing process wherein Sn(IV) in the SnO2 lattice gets partly converted to Sn(II) in the presence of hydrogen and the original species are recovered once the hydrogen atmosphere ceases to exist.