Initial Sticking Coefficient Attenuation of Gases in Carbon Monoxide Sensing on Pt80Au14Ti6

Abstract

Abstract It has been proved that Pt80Au14Ti6 can give proper signals as a CO sensitive layer in air at room temperature. Unfortunately, there is no signal anymore from this sample, if it is kept in air more than 24 hours. To overcome this problem, we carried out dry etching technic. The atmosphere testing also has been done in technic etcher chamber by keeping the samples separately in Ar, N2, CO, and O2 with pressure 1 atm for 24 hours without taking out the samples after etching process from the chamber. These experiments found that oxygen causes this loss signal problem. Oxygen can diffuse up to 170 Angstrom under the Pt surface to be subsurface oxygen. This diffusion changes the surface structure of Pt(100)(1x1) to hex-Pt(100) which impacts the attenuating of the initial sticking coefficient of gases. Simulations which have been conducted in this research produced the attenuating factor, i.e., 1 − 0.00585 exp (5.76664O sub), where O sub is the concentration of subsurface oxygen.