Functionalized Pt nanoparticles between α/γ-Fe2O3 and MXene for superior acetone sensing

Crystalline iron oxide (Fe2O3) shows great potential for acetone detection in multiple applications such as monitoring air pollution and diagnosing diabetes. α-Fe2O3 or γ-Fe2O3 are generally used as sensing materials. Here, we report a sol-gel method followed by a thermal treatment to control the phases formation of mesoporous iron oxide. We have found that mixed α/γ-Fe2O3 phases exhibit enhanced sensing performances toward acetone. Moreover, as α/γ-Fe2O3 is coupled with 2D materials of MXene (Ti3C2Tx), the agglomeration of Fe2O3 nanoparticles is prevented and the number of active sites for chemical absorption increased. Furthermore, the p-n heterojunctions lead to the enhancement of their response up to 148 towards 200 ppm of acetone at 200 °C. Additionally, Pt nanoparticles were be easily incorporated in between α/γ-Fe2O3 and MXene to reduce the operating temperature down to 160 °C, while maintaining a very high response (307 towards 200 ppm) and lowering the detection limit to 0.5 ppm, thanks to the catalytic properties Pt nanoparticles.