Bimetallic PtCu Nanocrystal Sensitization WO₃ Hollow Spheres for Highly Efficient 3-Hydroxy-2-butanone Biomarker...

As a foodborne bacterium, Listeria monocytogenes (LM) can cause serious diseases and even death to weak people. 3-Hydroxy-2-butanone (3H-2B) has been proven to be a biomarker for exhalation of LM. Detection of 3H-2B is a fast and effective method for determining whether the food is infected. Herein, we present an excellent 3H-2B gas sensor based on bimetallic PtCu nanocrystal modified WO₃ hollow spheres. The structure and morphology of the PtCu/WO₃ were characterized, and their gas sensitivities were measured by a static testing method. The results showed that the sensor response of WO₃ hollow spheres was enhanced by about 15 times after modification with bimetallic PtCu nanocrystal. The maximum response value of the PtCu/WO₃ sensor to 10 ppm 3H-2B is as high as 221.2 at 110 °C. In addition, the PtCu/WO₃ sensor also exhibited good selectivity to 3H-2B, fast response/recovery time (9 s/28 s), and low limit of detection (LOD < 0.5 ppm). Furthermore, the sensitivity mechanism was studied by monitoring the reaction products by gas chromatography-mass spectrometry. The excellent gas-sensing performance can be attributed to the synergy between PtCu and WO₃, including the unique spillover effect of O₂ on PtCu nanoparticles, the regulated depletion layer by p-type CuO to n-type WO₃, and their selective catalysis to 3H-2B. Hence, this work offers the rational design and synthesis of highly efficient sensitive materials for the detection of LM for food security.