Extraordinary room-temperature hydrogen sensing capabilities with high humidity tolerance of PtSnO2 composite nanoceramics prepared using SnO2 agglomerate powder

Two kinds of Pt SnO 2 composite nanoceramics have been prepared using SnO 2 nanoparticles and SnO 2 agglomerate powder separately. One is of a relatively uniform and porous microstructure with a specific surface area of 8.1 m 2 /g, and the other is of a rather non-uniform microstructure with large SnO 2 agglomerates and crack-like pores and a specific surface area of 6.4 m 2 /g. While the samples of uniform microstructure typically show a sensitivity of 150 to 1% H 2 – 20% O 2 – N 2 in air of 50% relative humidity (RH) at room temperature , those of non-uniform microstructure surprisingly show much higher sensitivities of 850 and 450 in air of 50% and 70% RH, respectively, to the same concentration of hydrogen. The influence of humidity on the samples has been further studied and a much higher humidity tolerance has been revealed for those samples of non-uniform microstructure. All these results demonstrate a clear and unexpected advantage of a non-uniform microstructure over a uniform one in humidity tolerance for room-temperature hydrogen-sensitive Pt SnO 2 composite nanoceramics.