Combustion synthesis of porous Pt-functionalized SnO2 sheets for isopropanol gas detection with a significant enhancement in response

Abstract

Pt-functionalized SnO₂ sheets with Pt contents of 0, 0.5, 1, and 2 wt% were synthesized by a facile solution combustion synthesis, and their crystal structure, morphology, and chemistry have been thoroughly characterized. In the combustion process, the urea (CO(NH₂)₂) has been employed as a fuel. The obtained products appear as porous sheets formed by the interconnected and loosely packed SnO₂ nanoparticles. Pt nanoparticles are assembled together with SnO₂ nanoparticles in several up to tens of nanometer clusters. The as-synthesized products were used as sensing materials in the sensors to detect the isopropanol (IPA) gas. Gas sensing tests exhibited that the Pt-functionalized SnO₂ are highly promising for gas sensor applications, as the operating temperature was lower than current IPA sensors and the response to IPA was significantly enhanced. The 2 wt% Pt–SnO₂ sheet based gas sensor displayed a response value of 190.50 for 100 ppm IPA at an optimized operating temperature of 220 °C, whereas the pristine SnO₂ based gas sensor only showed a response of 21.53 under the same conditions. The roles of Pt nanoparticles on electronic sensitization of SnO₂, catalytic oxidation (spillover effect), and the increased quantities of oxygen species on the surface of SnO₂ are plausible reasons to explain the significant enhancement in response to a Pt-functionalized SnO₂ sheet based gas sensor.