Study on humidity sensing property based on Li-doped mesoporous silica MCM-41

Pure and LiCl-doped mesoporous silica MCM-41 with different doping concentrations (1, 2, 5, 10 and 15 wt.%) have been prepared. XRD, IR spectra and SEM characterized the materials. These different characterization results suggest that these materials have the similar mesoporous structure. A resistive-type humidity sensor was fabricated on a ceramic substrate with Ag–Pd interdigital electrodes. The humidity sensing properties of the sensors were investigated at different frequencies. The studies revealed that the LiCl-doping was beneficial for improving the humidity sensing properties of the samples. The sample with 2 wt.% LiCl dopant has the best sensing properties to humidity. Finally, a possible mechanism is suggested to explain the humidity-sensitive properties.