Preparation and gas sensitivity of SnO₂ nanopowder homogenously doped with Pt nanoparticles

Platinum (Pt)-doped SnO₂ nanopowders were prepared by a new doping method which controls the surface charge by controlling the pH. Individual Pt particles were homogenously doped on the surface of the SnO₂ nanoparticles at pH 6. Subsequently, a heat treatment was conducted in a hydrogen atmosphere to remove contaminants and to increase the number of oxygen vacancies of the SnO₂ nanopowders. To recognize the sensitivity of the powders, Pt-doped SnO₂ gas sensors were fabricated using a dispensing technology on a silicon substrate and tested at 400 °C in ethanol and formaldehyde gas, and then compared with sensors fabricated with commercial powders. The test results showed that the SnO₂ gas sensors homogenously doped with Pt have sufficient sensitivity for detecting reducing gas.