Achieving a high long-term stability for room temperature CO-sensitive Pt-SnO2 composite nanoceramics through two strategies

Pt-SnO2 composite nanoceramics with 1, 2, 5, and 10 wt% Pt separately were prepared through pressing and sintering. All samples showed strong and fast response to CO at room temperature. The responses of samples of 1, 2, 5 wt% Pt decreased very quickly with time, while that of samples of 10 wt% Pt was much more stable. Brief heat-treatments had been tested and the CO-sensing capability of a 384 h aged sample of 10 wt% Pt was fully restored to that as-sintered through a heat-treatment of 200 degrees C for 10 min. It is proposed that the deposition of impurity gases in air results in the observed aging and brief heat treatments are able to remove them. Two closely related strategies, namely a suitable Pt content and a periodic heat-treatment, are suggested for room temperature CO-sensitive Pt-SnO2 composite nanoceramics to ensure a high long-term stability and a reasonable cost simultaneously.