Effect of doping method on the morphological and gas sensing properties of Pt:SnO2 pellets

Platinum doped tin oxide (SnO₂: Pt) powders were obtained by employing novel methods, which are a mixture of chemical and physical synthesis methods. The powders were prepared from tin chloride and urea as precipitant agent. The resultant SnO₂ powders are milled in a planetary ball mill. Finally, a noble metal, platinum (Pt), was added to the milled SnO₂ powders via bulk and surface doping methods, and then pressed with a pressing machine to manufacture thin pellets. After several experimental trials, stable Pt: SnO₂ pellets were formed. Later, silver contacts were manufactured on the pellets surface by the thermal evaporation technique. The effect of Pt adding methods on the morphological properties is presented in this work. The morphological study was developed by using Scanning Electron Microscopy (SEM), and High Resolution Transmission Electron Microscopy (HRTEM) analysis. Additionally, the sensing properties of these pellets as a function of the gas concentration were measured in carbon monoxide (CO) atmosphere at different operation temperatures.