Ruthenium: tin oxide thin film as a highly selective hydrocarbon sensor

Abstract The gas sensing properties of ruthenium-doped tin oxide thin films prepared by spray pyrolysis has been studied. The thin film with composition of ruthenium (0.42 wt.%) in the tin oxide matrix spray pyrolysed at 400 °C, has shown unusual high sensitivity (s=2500) for hydrocarbon (LPG) at a lower operating temperature of 250 °C. It has been shown that ruthenium acts as a catalyst in tin oxide to achieve a considerable degree of specificity and selectivity. The low temperature deposition with the dual use of noble metal ruthenium as a sensitizer and a sintering aid has remarkably enhanced hydrocarbon sensing performance. A systematic evaluation of the surface coverage and morphology using techniques like energy dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM), and X-ray diffraction (XRD) reveal the crucial role of ruthenium species in both sensitivity and selectivity of LPG gas. The correlation between ruthenium incorporation in tin oxide thin film and improvement in the selectivity and sensitivity towards hydrocarbon (LPG) is established.