CuxCryOz mixed oxide as a promising support for gold – The effect of Au loading method on the effectiveness in oxidation reactions

CuxCryOz containing copper–chromium oxide spinel and CuO was used as a support for gold loaded by different methods: deposition–precipitation using KOH, deposition–precipitation using urea and gold–sol method with tetrakis(hydroxymethyl)phosphonium chloride. The technique of modification with gold determined not only the Au particle size (the smallest if gold–sol method was used) but also the number of oxygen vacancies and copper concentration on the surface. All these parameters were considered in the study of CO, glycerol and methanol oxidation. The size of gold particles is a key feature determining the activity in the oxidation of CO. Glycerol oxidation is also sensitive to this parameter but less than CO oxidation. The oxidation of methanol is not influenced by the presence of gold and it occurs on the CuxCryOz support.

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► Oxygen vacancies created on CuxCryOz by gold loading depend on modification method.
► The gold introduction effects the chemical composition of CuxCryOz catalyst.
► The catalytic role of gold on CuxCryOz depends on type of the oxidation reaction.