Roles of nano-sized Au in the reduction of NOx by propene over Au/TiO2: An in situ DRIFTS study

A mechanistic study of the selective catalytic reduction (SCR) of NOx by C3H6 has been investigated over nano-sized Au/TiO2 catalyst using in situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS). The formation and consumption of adsorbed species on the catalyst surface have been intensively studied during co-adsorption of reactants and reaction condition. The presence of nano-sized Au particles played an important role in the formation of oxygenated hydrocarbons, especially acetate species. Importantly, Au active sites were crucial to the formation of isocyanate intermediate compounds and contributed to the conversion of these intermediates to N2. The reaction mechanism of SCR over Au/TiO2 has been discussed on the basis of DRIFTS results.