Effect of Co and Fe substitution on catalytic VOCs removal on zinc aluminate

• Co and Fe substituted ZnAl2O4 were prepared by microwave-assisted glycothermal way.
• Substitution of ZnAl2O4 strongly modifies its physicochemical properties.
• ZnAl2O4 substitution leads to improvement in catalytic performance for C3 combustion.
• Fe-containing spinels were found to be more active than Co-containing ones.
• Pt/spinels catalysts show very good C3 combustion activity with some support effect.

Co and Fe substituted ZnAl2O4 were prepared by microwave-assisted solvothermal method and their catalytic properties were tested in the total oxidation of lean propane as catalysts or supports for platinum catalyst. Substitution of ZnAl2O4 by Co and Fe ions modifies its structural, textural and acid–base properties as well as reduction behavior and particle morphology. As a result, improvement of the catalytic activity was observed: light-off curves were shifted towards lower temperatures and propane combustion rates were higher by 60% for the Co-substituted spinels and by 100% for the Fe-containing spinels. Pt catalysts revealed superior catalytic activity as compared to the pure and substituted spinels and some support effect was observed. Namely, platinum deposited on the Co-substituted spinels possesses higher activity than that on the ZnAl2O4 and Fe-containing spinels. We suppose that acid–base properties of the support materials and Pt particle size influence on the intrinsic Pt oxidation activity. It was found that small Pt particles (∼0.9 nm) deposited on the support with the highest acidity (Zn0.5Co0.5Al2O4) exhibited the highest activity.

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