Surface modification of nanosheet-type tin oxide with Au-Pd for hydrogen gas sensing

A thin film consisting of a nanosheet-type tin oxide (SnO2) was synthesized on a sensor chip via the aqueous solution process. Au-Pd was then loaded on its surface via ion sputtering. The sensor signal response of the Au-Pd loaded nanosheet-type tin oxide to hydrogen was higher than that of the bare nanosheet-type tin oxide, while its signal response to methane gas decreased. The 42% covered nanosheet-type tin oxide (30 s sputtering) resulted in the highest H2/CH4 response ratio. The high sensor signal response to hydrogen was attributed to the hydrogen spill-over effect, the oxygen back spill-over effect, and the (101) crystal facet on the surface of the nanosheet-type tin oxide. The designed nanosheet has potential applications as a hydrogen sensor array.