Rationally Designed Dual-Mesoporous Transition Metal Oxides/Noble Metal Nanocomposites for Fabrication of Gas Sensors in Real-Time Detection of 3-Hydroxy-2-Butanone Biomarker

Transition metal oxides/noble metal (TMOs/NM) nanocomposites are one kind of important material for semiconductor gas sensors. The controllable construction of a highly connected mesoporous structure and easily accessible active sites is essential for gas sensing performance but remains a great challenge. Herein, a soluble mercapto phenolic resin polymer mediated co-assembly approach is proposed for the construction of ordered dual mesoporous structure and the simultaneous loading of highly dispersed noble metal nanoparticles. The home-made soluble mercapto phenolic resin polymer enabled the co-assembly of transition metal precursors, noble metal precursors, and poly(ethylene oxide)-block-polystyrene (PEO-b-PS) micelles, resulting in a straightforward synthesis of ordered dual-mesoporous TMOs/NM nanocomposites (e.g., WO3/Au, TiO2/Au, NbOx/AuPd). As proof of the concept, the synthesized dual-mesoporous WO3/Au materials are applied for sensing of 3-hydroxy-2-butanone, a biomarker of food-borne pathogenic bacteria Listeria monocytogenes. The sensors exhibit high sensitivity (R-a/R-g = 18.8 to 2.5 ppm) and high selectivity based on their noble metal sensitization and superior mesopore connectivity for gas diffusion. Furthermore, the synthesized gas sensors are integrated into a wireless sensing module connected to a smartphone, providing a rapid and convenient real-time detection of 3-hydroxy-2-butanone.

Automated summary

A polymer-mediated co-assembly method was proposed for the construction of highly connected mesoporous structures and the simultaneous loading of noble metal nanoparticles in TMOs/NM nanocomposites. The materials showed high sensitivity and selectivity in gas sensing performance, with the sensors integrated into a wireless module connected to smartphones for real-time detection of specific biomarkers.