Polyoxometalate\nCluster-Guided Dynamic Nucleation\nand Hierarchical Growth of Branched WO<sub>3</sub> Nanofibers with\nUltrafine Pt Nanoparticles for Advanced Gas Sensing

In the food industry, 2,3-butanedione is a significant\nvolatile\norganic compound valued for its unique aroma and flavor. Real-time\ndetection of its concentration during food preparation is crucial\nfor ensuring optimal taste and food safety. However, accurately detecting\nlow concentrations of 2,3-butanedione requires highly sensitive sensing\nmaterials. Herein, we present a novel synthesis of branched WO<sub>3</sub> nanofibers decorated with ultrafine Pt nanoparticles (Pt\nNPs-WO<sub>3</sub> NFs), templated by polyoxometalate (POM) clusters,\nthrough a combination of electrospinning and thermal oxidation strategies\nfor advanced gas sensing applications. This Pt NPs-WO<sub>3</sub> NFs-based\nsensor exhibits impressive sensitivity (<i>R</i><sub>a</sub>/<i>R</i><sub>g</sub> = 2.25 vs 500 ppb), a low detection\nlimit of 10 ppb, high selectivity, excellent repeatability, and stable\nperformance over a period of 25 days. Using POM clusters as templates\noffers significant advantages over the traditional WCl<sub>6</sub> salt in synthesizing WO<sub>3</sub> NFs with smooth surfaces. Specifically,\nthe POM clusters guide the dynamic nucleation and hierarchical growth\nof branched NFs, enhancing the concentration of oxygen vacancies and\nincreasing the number of active adsorption sites. Furthermore, the\nuniform dispersion of ultrafine Pt NPs (≈ 4 nm) within the\nWO<sub>3</sub> NFs further enhances the catalytic activation of 2,3-butanedione,\nsignificantly improving the gas sensing performance. This study introduces\nan efficient method to synthesize Pt NPs-WO<sub>3</sub> NFs with potential\nfor manufacturing advanced nanostructured sensing materials using\nPOM clusters as templates, paving the way for high-performance gas\nsensing technologies.