Platinum decorated iron tin oxide solid solutions for hydrogen gas sensing
The hydrogen gas monitoring is important in numerous applications such as in the semiconductor manufacturing, aerospace applications and metallurgical processes. Among the developed hydrogen sensors, those based on semiconducting metal oxides have attracted attention due to their relative high sensitivity, long lifetime and thermal stability. In this project the hydrogen gas sensing properties of pristine SnO2 and Fe2O3 as well as of Fe2xSn2-2xO4-x solid solutions will be studied. SnO2 doping with iron will cause changes in lattice parameters and bond length, number of oxygen vacancies, and will have an impact on the narrowing SnO2 band gap. It is expected that the formation of iron tin oxide solid solution (Fe2xSn2-2xO4-x) will decrease sensor operating temperature and will have beneficial effect on the synthesized sensors sensitivity. The selectivity to hydrogen will be improved by platinum (Pt) decoration on the surface of synthesized samples. In this project the microstructural properties of synthesized metal oxide supports will be optimised using divalent anhydrous iron(II) and tin(II) acetates. The divalent Fe(II) and Sn(II) metal cations will be oxidised and hydrolysed using water molecules generated “in situ” in the esterification reaction between acetate groups and ethanol. The decoration of Pt clusters on the synthesized Fe2O3, SnO2 and Fe2xSn2-2xO4-x supports will be optimised using Pt(II) acetylacetonate precursor. The same set of samples will be synthesized using ball-milling (solid state synthesis) and microwave assisted solvothermal synthesis (bottom-up wet chemistry approach). Using two different synthesis techniques will enable us to determine the optimal solid solution formulation for the highest Pt-catalyst dispersion in order to accomplish the best hydrogen gas sensing properties. This project may be the first step in the development and production of new gas sensor materials and in the construction of commercially available gas-sensing system.