Ultrasensitive sensing performances to sub-ppb level acetone for Pd-functionalized SmFeO3 packed powder sensors

Abstract

Pd-SmFeO₃ is functionalized by mixing PdCl₂ with nanocrystalline powders and subsequently followed by an annealing at 750 °C. With an increasing amount of Pd²⁺ in composite powders, the sensing response R_g/R_a for low concentration acetone for Pd-doped SmFeO₃ sensors increases at first, reaching a maximum with 3 wt% PdCl₂ dopant, and then decreases again. The response for undoped SmFeO₃ at 240 °C is 2.26 to 500 ppb acetone, whereas the response for 3 wt% Pd-SmFeO₃ at 240 °C is 7.21 to 500 ppb acetone. The 3 wt% Pd-doped SmFeO₃ sensor at 240 °C shows a short response time (8 s) and recovery time (15 s) to 500 ppb acetone gas, respectively. Such results show that 3 wt% Pd-doped SmFeO₃ sensor is a new promising sensing candidate for detecting low concentrations of acetone. Cross-response to relative humidity has also been considered. With increase of relative humidity (RH), there was a slight reduction in response. When the relative humidity is 80% RH, 3 wt% Pd-SmFeO₃ to 500 ppb acetone response is 3.25. The superior response and response to acetone gas offer a potential platform for application in diabetes diagnosis.