Cookie like Au/NiO nanoparticles with optical gas sensing properties

During the last 20 years, syntheses of nanoparticles with different sizes, shapes, compositions, and structures have been developed to create and study new nanomaterial properties. For example, light emission from semiconductor quantum dots can be controlled by tailoring the size, size distribution, and surface states of the particles. The optical properties of metal nanoparticles also depend on their size, size distribution, and morphology. Different synthesis methods have been developed for preparing nanoparticles with a core/shell structure (e.g., CdSe@ZnS or Au@SiO2), or for controlling their morphological features (e.g., semiconductor rods, stars or triangles, and metal rods), thus allowing the preparation of nanostructured materials with unique functional properties. In this paper we report for the first time the synthesis of “cookie”-like Au/NiO nanoparticles showing unique optical gas-sensor properties.