MOF-derived TiO2 nano-disks decorated with Pt nanoparticles for enhanced acetone sensing

Abstract

Platinum (Pt)-modified titanium dioxide (TiO₂) nanodisks, derived from metal–organic frameworks (MOFs), were developed to enhance the detection of volatile organic compounds (VOCs), particularly acetone. The introduction of Pt nanoparticles resulted in significant modifications to the crystal structure, morphology, defect density, and chemical composition of the TiO₂ nanodisks. The anatase (21.26 nm) and rutile (30.08 nm) phase crystallites within the 1 wt% Pt–TiO₂ (1PTO) sample demonstrated the smallest average size among all samples examined. Analysis via X-ray photoelectron spectroscopy (XPS) revealed the presence of both Pt⁰ and Pt⁴⁺ oxidation states in the 1PTO sample, thereby demonstrating partial reduction of the platinum precursor. An evaluation of gas sensing performance using acetone as the target analyte revealed exceptional performance of the 1PTO sensor. The Pt modification significantly enhanced sensing performance by lowering the optimal operating temperature (from 250 °C to 225 °C) and improving the sensor response. Specifically, at 225 °C and a concentration of 1 ppm acetone, the response value was measured at 12.12, with response and recovery times of 13 and 4 seconds, respectively. Based on the results of comprehensive characterization and VOC testing, a detailed acetone sensing mechanism is proposed.