performance improvement [6].
To profit from the textural properties of alumina and the stabilizing
effect of NiAl2O4 spinel as a support for Pd catalysts, in this
work, we present a facile way to stabilize the performance of Pd/
Al2O3 for lean CH4 catalytic combustion by introducing spinel
NiAl2O4 interface as a promoter at no cost to the activity and morphology
degradation of the support. A series of Pd/xNiO/c-Al2O3
with NiO loadings varying from 0.5 to 9.0 wt.% is investigated.
Pd/0.5NiO/c-Al2O3 with a low Pd loading of 0.4 wt.% demonstrates
higher Pd utilization efficiency than state-of-the-art Pd-based catalysts,
with a >99% initial CH4 conversion and a remaining >94%
conversion after reaction for 50 h at 400 C. The relation between
the catalytic activity and the effect of NiO additives and spinel
NiAl2O4 interface formation is discussed. Against the background
of this study, the cost efficiency, high activity, and good stability
of the minor nickel-promoted Pd/xNiO/c-Al2O3 catalysts make
them of potential interest for the ignition of a natural gas combustor
and low-temperature CH4 exhaust treatment.