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

•The porous bi-phase α-/γ-Fe2O3 nanoparticles are derived from MIL-53(Fe) for the first time.•The assembling of porous bi-phase α-/γ-Fe2O3 nanoparticles in exfoliated Ti3C2Tx nanosheets generates high-performance α-/γ-FT-X acetone sensing material.•Improved sensitivity due to multiple heterojunction interfaces, surface defects, and porosities.•Novel sensing mechanism is proposed and investigated.