Effect of flame-made metal (M=Pt, Nb, Ru)-Loaded In<inf>2</inf>O<inf>3</inf>on NO<inf>2</inf>gas sensing

Abstract

Unloaded In2O3and M (M=Pt, Nb and Ru)-loaded In2O3nanoparticles loaded with 0.25-1.00wt% M were successfully synthesized in a single step by the flame spray pyrolysis (FSP) technique. Indium nitrate, platinum (II) acetylacetonate, niobium ethoxide and ruthenium (III) acetylacetonate were used as In, Pt, Nb and Ru precursors respectively, dissolved in ethanol. The unloaded In2O3and M-loaded In2O3nanoparticles were characterized. The average diameter of the spherical nanoparticles were in the range of 10.2 to 15.2 nm under 5/5 (precursor/oxygen) flame conditions. All peaks can be confirmed to correspond to the cubic structure of In2O3(JCPDS No. 03-065-3170). Gas sensing studies showed that Pt-loaded In2O3gave an enhancement in NO2sensing in term of response and selectivity. 0.5wt% Pt/In2O3exhibited good selectivity against H2S and NO gases. When compared to other metal loading such as Nb and Ru, Pt-loaded In2O3exhibited much better gas sensing against NO2, H2S and NO gases.