Synthesis and characterization of novel Au/θ-Al2-xFexO3 nanomaterials with high thermal stability in catalytic oxidation of carbon monoxide

•Au° nanoparticles are formed on the θ-Al2-xFexO3 support at 300 °C.•Complete elimination of organic compounds proceeds only at 500 °C in air.•Au particle size distribution is narrow at 2 nm (300 °C) and 3.4 nm (500 °C).•Prepared materials are highly active catalysts of CO oxidation in the NH3 presence.•No changes in the catalytic activity even after prolong annealing the material at 750 °C.

Applications as a catalyst in engine exhaust systems require a uniform distribution of gold nanoparticles on a thermally stable alumina support. The novel thermally stable nanomaterials comprised of gold nanoparticles on the iron-modified theta-alumina support have been synthesized by the method of deposition-precipitation using urea. The material precursor was proved to involve both a gold precursor and adsorbed urea. The generation of gold nanoparticles from the gold precursor occurred below 300 °C, whereas the complete elimination of organic compounds proceeded only at 500 °C in air or even at 650–700 °C in a reducing gas flow. The gold particle size distribution was narrow with a mean size about 2 nm and 3.4 nm after calcination at 300 °C and 500 °C respectively. The prepared materials are highly active and stable as the catalysts of carbon monoxide oxidation in the presence of ammonia, and maintain the catalytic activity even after prolong thermal treatment at 750 °C.

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