Hydrogen-reduced Cu/ZnO composite as efficient reusable catalyst for diesel particulate matter oxidation

•Hydrogen reduced Cu/ZnO composite (5%Cu) manifested a strong diesel particulate matter oxidation activity at 150 °C.•Cu1+ at the catalyst surface was found to be responsible for the high catalytic activity.•High stability of Cu1+ is assigned to the isoelectronic interactions of Cu1+ with Zn2+.•The catalyst can be used even from the starting moment of the diesel engines.

Hydrogen-reduced copper-loaded ZnO (Cu/ZnO) showed a strong diesel particulate matter oxidation activity at temperature as low as 150 °C. Cu/ZnO catalyst with 5% nominal Cu content was tested for the oxidation of diesel particulate matter under air flow between 25 and 800 °C. The high catalytic performance of reduced 5%Cu/ZnO even after its use in diesel particulate matter oxidation has been assigned to the presence of Cu1+ ions at its surface, determined by Auger electronic spectroscopy. The high stability of Cu1+ could be assigned to the isoelectronic interaction of Cu1+ (3d10) with Zn2+ (3d10) at the Cu2O–ZnO interface. Results presented in this work indicate that the composite catalyst can be considered as part of an exhaust catalytic system, for abating diesel particulate matter emission at low temperature.

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