Au/Cu-Fe-La-Al2O3: A highly active, selective and stable catalysts for preferential oxidation of carbon monooxide

- Copper precursor was added to a FLA support via wetness impregnation method before Au deposition.
- High dispersion of Au nanparticles, formation of Au-Cu alloy, and the close contact of single or alloyed Au nanoparticles to CuO species which makes Au partially positively charged.
- Copper addition improved overall performance for PROX but lowered activity in O2-rich stream.
- More Au-CuO interfaces or positively charged gold play a crucial role in promoting CO2 formation in CO-PROX reaction.

A series of gold-based catalysts supported by Fe-La-Al2O3 composite doped with various amounts of copper were prepared using a modified deposition-precipitation method. Investigations were carried out based on the reaction of the preferential carbon monoxide oxidation (CO-PROX) in H2-rich stream and CO oxidation at low temperatures in an O2-rich stream as a reference to examine the effects of copper on the catalytic performance. The high dispersion of gold nanoparticles in alumina-based support, the formation of Au-Cu alloy, and the close contacts of these neat or alloyed nanoparticles with CuO species, making Au partially positively charged, were examined with H2-TPR, XPS, and HRTEM-FFT techniques. Gold catalysts were obtained with very promising performance for polymer electrolyte membrane fuel cell with positive results in activity, CO2 selectivity, and thermal stability and long-term storage and on-line stability. Although H2 addition decreased the rate of CO oxidation over the studied gold catalysts, the activity and selectivity in CO2 formation were continuously improved with an increase in copper loading.

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