Assembling a high-performance acetone sensor based on MOFs-derived porous bi-phase alpha-/gamma-Fe2O3 nanoparticles combined with Ti3C2Tx nanosheets

Acetone is one of the volatile organic compounds (VOCs), which is found in precarious both human health and the environment. For efficient detection of acetone gas concentration and leakage, we have successfully synthesized stable alpha-/gamma-Fe2O3/ex-Ti3C2Tx-X gas sensing material via in-situ solvothermal and calcination method, in which MIL-53(Fe)-derived porous bi-phase alpha-/gamma-Fe2O3 nanoparticles uniformly growing on the surface and interlayers of exfoliated Ti3C2Tx nanosheets (alpha-/gamma-FT-X). The numerous heterojunction interfaces, surface defects, and porosities of alpha-/gamma-FT-X composites can simultaneously facilitate the diffusion process and contact interaction between acetone molecules and active sites. Strikingly, the optimal alpha-/gamma-FT-4 composite possesses the superior sensitivity (R = 215.2) towards 100 ppm acetone at 255 degrees C, which is nearly 8 times higher than that of alpha-/gamma-Fe2O3 (R = 26.2) and much higher than exfoliated Ti3C2Tx nanosheets (R = 3.8), respectively. Moreover, fast response (13 s) and recovery (8 s) properties are achieved, as well as outstanding repeatability and remarkable selectivity. An enhancement mechanism for alpha-/gamma-FT-4 composite is proposed and investigated. It is expected for us to open an effective avenue for fabricating efficient acetone sensing materials.