Gold (Au) is a soft, metallic substance that has been fabricated into intricate shapes since ancient times. It is a very dense metal with a face-centered cubic crystal structure, and it is ductile, allowing it to be shaped without the need for sophisticated metalworking equipment. Gold is also resistant to corrosion and has excellent electrical conductivity. This resistance to corrosion and conductivity, along with its high melting point and ductility, make it very useful for making jewelry, decorative objects, and coins.

oxide gold is an inorganic compound with the chemical formula Au2O3. It is the most stable form of gold, and a brown or brownish-black powder at room temperature. It is soluble in toluene, concentrated nitric acid, and sodium cyanide solution. It is also insoluble in water, although it can be dissolved in aqua regia.

Despite these unique properties, oxide gold is very difficult to produce. The ore must first be crushed and smelted to release the gold from sulfide and arsenic minerals; then it is leached using a series of solvents, followed by heap leaching. Despite these difficulties, refractory gold accounts for 22 percent of global reserves.

In this study, we investigated the ability of Au deposited on silica nanoparticles to resist CO oxidation by employing IRAS spectroscopy. Unlike other studies that have found that gold deposited on SiO2 is susceptible to CO oxidation, our results show that gold deposited on silica nanoparticles is not only thermally stable but is also somewhat resistant to sintering, even after UHV annealing to 600 K. Moreover, XPS analyses of the Au/nano-SiO2 samples showed that a strong correlation between BE values and particle size was observed.