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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