Quantitative Measurements Of Adsorbed Oxygen Species on Material Surface For High-Performance Gas Sensor Design

This work reports the quantitative measurements of adsorbed oxygen species {(${{\text{O}}_2}^ - $ (α state), O
^-
(β state), and O
^2-
( γ state)} on the surface of octahedral SnO
2
nanoparticles as gas sensing material by microcantilever-based temperature-programmed desorption (cantilever-TPD) technique. Based on the ultrahigh mass sensitivity of the integrated resonant microcantilever, the tiny mass change (∆m) due to the oxygen species desorption during the heating process can be precisely measured, while only requires nanogram (ng)-level sample. The cantilever-TPD results suggest that the octahedral SnO
2
nanoparticles after H
2
gas treatment exhibit increased amount of β(O
^-
) species, which means an enhanced sensing performance. The response of the H
2
-treated sample to ethanol at the optimal working temperature of 360°C is about two-fold as high as that of the untreated counterpart.