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

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 degrees 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 O-2 on PtCu nanoparticles, the regulated depletion layer by p-type CuxO 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.