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gold catalysts, nanoparticles, zeolites, FTIR, UV-visible spectroscopy
Catalysis by gold
Abstract:
Electronic states of gold nanoparticles in mordenite and their transformations under redox treatments have been studied by the methods of FTIR spectroscopy of adsorbed CO and diffuse reflectance UV-visible spectroscopy. Different states of ionic and metallic gold were detected in the zeolite channels and on the external surface of the zeolite – Au+ and Au3+ ions, charged clusters Aunδ+, and neutral nanoparticles Aum. Catalytic tests of the samples revealed the existence of two types of active sites of gold in CO oxidation – gold clusters < 2 nm (low-temperature activity) and gold nanoparticles (high-temperature activity