Evaluate humidity sensing properties of novel TiO2–WO3 composite material

A novel TiO2–WO3 composite material was prepared using a different proportion of TiO2 and WO3 to that investigated in previous studies. The obtained mesoporous material was characterized using X-ray diffraction, Fourier transform infrared spectrometry, transmission electron microscopy, energy dispersive X-ray spectroscopy, and N2 adsorption-desorption techniques. The humidity-sensing properties were measured using an inductance, capacitance and resistance analyzer. The results demonstrated that the TiO2–WO3 sample with a ratio of 1:1 showed better humidity sensing properties. Compared to previous studies, the prepared sensor exhibited higher sensitivity (S = 451) and the lower hysteresis value was around 0.13% at 32% RH. Complex impedance analysis indicated that the enhanced humidity sensitivity was probably due to spherical Brunauer–Emmett–Teller surface area and the hetero-junction between TiO2–WO3 thin films, while the impedance varied about three orders of magnitude. Our results demonstrated the potential application of TiO2–WO3 composite for fabricating high performance humidity sensors.