Enhanced methane combustion performance over NiAl2O4-interface-promoted Pd/γ-Al2O3

• Spinel NiAl2O4 was formed over alumina surface by impregnation and calcination.
• NiAl2O4 interface promotes the distribution and crystallization of PdO.
• NiAl2O4 interface affects interaction between alumina support and PdO.
• NiAl2O4 interface enhances the stability of Pd/Al2O3 at no cost of activity.

Poor durability and low Pd utilization efficiency are the main drawbacks of supported Pd catalysts for low-temperature methane combustion. Here, we present a facile way to stabilize the performance of Pd/Al2O3 by introducing a spinel NiAl2O4 interface as a promoter at no cost to the activity. The NiAl2O4 interface is formed by impregnation of alumina supports in the nickel-containing solution, followed by high-temperature calcination. A series of 0.4 wt.% Pd/xNiO/γ-Al2O3 with NiO loading varying among 0.0, 0.5, 1.0, and 9.0 wt.% is investigated. The formation of a NiAl2O4 interface promotes the distribution and crystallization of PdO, suppresses PdO particles aggregation and surface OH− species accumulation during the reaction, and finally leads to the excellent performance of Pd/0.5NiO/γ-Al2O3. Pd/0.5NiO/γ-Al2O3 demonstrates higher Pd utilization efficiency than the state-of-the-art Pd-based catalysts and better stability than Pd/Al2O3. Such a spinel interface promotion strategy may bring new insight into the design of highly efficient Pd-based catalysts and their potential technological applications.

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