Coupling interface design of metal oxide heterostructures derived from MXene@MOFs hybrids for high-sensitivity acetone sensor.

Acetone is used in a variety of fields for being highly volatile chemicals that may have detrimental effects on both industrial security and human health. With a view to testing the leak and concentration of acetone, we have successfully developed TiO 2 /Fe 2 O 3 -X (TF-X) sensors via a carboxyl group-shared coordination route. Here, Ti 3 C 2 T x MXene and Fe salt provide chelation sites enabling coordination with carboxyl groups to fabricate two kinds of MOFs (MIL-125(Ti)/MIL-53(Fe)) followed by calcination. The tightly coupled heterogeneous interface between TiO 2 and Fe 2 O 3 promotes carrier transfer and elicits sharp resistance variation thereby raising the sensitivity towards acetone. Meantime, the porous TF-X heterostructures generate numerous oxygen vacancies and surface functional groups to be conducive to the gas flow and surface reaction. Accordingly, the optimal TF-400 heterostructure endows the extraordinary sensitivity (R = 446.8) to 100 ppm acetone at 268 ℃, much higher than that of the pristine TiO 2 and Fe 2 O 3. Rapid response (15 s) and recovery (7 s) time are implemented, as well as remarkable selectivity and stability. Moreover, the enhanced mechanism of TF-400 heterostructure is presented and studied. It is anticipated to open up a new avenue for the design and synthesis of high-sensitivity acetone sensors. [Display omitted] • An artful strategy of MXene and Fe salts as bimetallic sources is first proposed. • The TF-X heterostructures make for carrier migration and resistance modulation. • The surface defects and functional groups raise the sensitivity of porous TF-X. • The reaction mechanism is proposed and investigated. [ABSTRACT FROM AUTHOR]