Steam reforming of CH4 over Ni-Ru catalysts supported on Mg-Al mixed oxide

Ni0.5/Mg2.5(Al)O catalyst prepared from hydrotalcite precursors showed high and stable activity in the CH4 steam reforming, but was severely deactivated in the daily start-up and shut-down (DSS) operation under steam purging. The addition of Ru drastically improved the behavior of Ni0.5/Mg2.5(Al)O catalyst for the DSS operation. During the wet Ru loading on the Ni0.5/Mg2.5(Al)O catalyst, the reconstitution of hydrotalcite took place by "memory effect," resulting in the formation of Ru-Ni alloy as well as the strong interaction between Ru and Ni after the calcination followed by reduction. This provided the catalyst with high sustainability probably by suppressing the oxidation of Ni metal by steam by hydrogen spillover from Ru. Only 0.05 wt% of Ru loading was enough to effectively suppress the deactivation