Engineering metal oxide heterostructures derived from MOFs/MXene hybrids as efficient acetone sensor

Acetone, one of the most used solvents in industry and the laboratory, can anesthetize the central nervous system of humans and cause damage to the kidneys, pancreas, and liver. For the purpose of monitoring the leakage and concentration of acetone, α-/γ-Fe2O3/TiO2-X (α-/γ-Fe2O3-X) materials were successfully manufactured by in-situ solvothermal and calcination processes. Here, MIL-100-derived porous α-/γ-Fe2O3 and TiO2 nanoparticles are uniformly grown on the self-sacrificial template of exfoliated Ti3C2Tx nanosheets (ex-Ti3C2Tx) that simultaneously serve as the Ti source. The heterostructure between TiO2 and Fe2O3 therein is conducive to carrier transfer and sharp resistance change. And bulk resistance-controlled γ-Fe2O3 is able to raise the response to gas. Besides, the porous structure of α-/γ-Fe2O3-X could create plenty of oxygen vacancies and surface functional groups, which facilitate diffusion and contact interaction between acetone and active sites. Accordingly, the α-/γ-Fe2O3-X endow exceptional response (R = 105.5) towards 100 ppm acetone at 240 ℃, fast response/recovery time, outstanding selectivity and stability. To further substantiate this promotion mechanism, density functional theory (DFT) calculations were carried out for investigating the adsorption behavior of α-/γ-Fe2O3-X for acetone.