Pr-promoted Ni exsolution from Ni-Mg-Al (O) as catalysts for syngas production by dry reforming of methane

We report the preparation by three methods (coprecipitation, self-combustion, and microwave-assisted self-combustion) of Pr-promoted Ni-catalysts for H-2/CO>1 syngas production by dry reforming of methane (DRM). The catalysts were characterized by a package of techniques to describe their physicochemical properties including several techniques using CO2 as a probe molecule. The catalysts were tested at 600 degrees C (10 h) and 120 L.g(-1) h(-1), without previous H-2-reduction. The coprecipitation method allowed obtaining a catalyst with a higher surface area and CO2 capture capacity (3.1 mg.g(cat)(-1)), a higher number of basic sites, lower average Ni-0 particle size (5.5 nm), higher catalytic conversions (48-65% of CH4 and 39-42% of CO2) and H-2 (H-2/CO = 1.15-1.75) yield but higher C formation. In addition, the catalyst obtained by microwave-assisted self-combustion presented better performance (45-51% of CH4 and 35-38% of CO2) than traditional self-combustion (40-45% of CH4 and 33-35% of CO2). The results showed that not only Ni-0 particle size but also the presence of basic sites with high thermal stability and grain morphology affect the catalytic activity and coke formation.