Rational design of Au/Co3O4-functionalized W18O49 hollow heterostructures with high sensitivity and ultralow limit for triethylamine detection

The rational design of heterostructures is highly important for innovative sensor technology to acquire efficient gas detection with optimized gas sensing properties. In the present work, a novel heterostructure of Au/Co3O4/W18O49 hollow spheres is constructed and applied for gas sensor application. The structure-property correlation has been studied by means of X-ray diffraction, X-ray photoelectron spectroscopy, Scanning electron microscope and Transmission electron microscope, as well as comprehensive gas sensing tests. Experiments demonstrate that the Au/Co3O4/W18O49 heterostructure delivers outstanding performances in terms of high sensitivity, fast response-recovery, good selectivity, and very low limit of detection against pristine W18O49 and Co3O4/W18O49. Notably, a very high response (16.7) to 2 ppm triethylamine and a state-of-the-art limit of detection (81 ppb) are obtained. The superior gas sensing properties are attributed to a synergistic combination of the unique porous structure, the p-n heterojunctions between Co3O4/W18O49, and the catalytic spillover effect of Au nanoparticles.