CO2 gas sensing response of YPO4 nanobelts produced by a colloidal method

YPO4 has been studied as host lattice for luminescence materials; however, little is known about its gas sensor properties. In this work, YPO4 was synthesized by a colloidal method using yttrium nitrate, phosphorous acid and CTAB (as surfactant). The calcination at 500 °C produced single-phase YPO4 nanobelts, having length between 3 and 10 μm, and width between 70 and 250 nm. In order to optimize the synthesis of YPO4 nanobelts, several surfactants and different concentrations of CTAB were tested. Impedance measurements were performed on thick films made with the as-prepared YPO4 nanobelts. The results show repeatability in the detection of variations in the concentration of CO2 of 200 ppm, from 350 °C. However, the response was improved, when an operating temperature of 400 °C was used. At this temperature YPO4 responded in a wider frequency range, from 100 Hz to 100 kHz. Quantitative detection of CO2 was proposed in terms of the variation on the dielectric constant of the carbonate film, formed on its surface. Preliminary results obtained from carbon monoxide sensing characterization revealed a periodic detection pattern, with short response time. These results indicate a p-type semiconductor behavior for YPO4.