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

Abstract

We report the preparation by three methods (coprecipitation, self-combustion, and microwave-assisted self-combustion) of Pr-promoted Ni-catalysts for H2/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 °C (10 h) and 120 L∙g−1 h−1, without previous H2-reduction. The coprecipitation method allowed obtaining a catalyst with a higher surface area and CO2 capture capacity (3.1 mg∙gcat−1), a higher number of basic sites, lower average Ni0 particle size (5.5 nm), higher catalytic conversions (48–65% of CH4 and 39–42% of CO2) and H2 (H2/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 Ni0 particle size but also the presence of basic sites with high thermal stability and grain morphology affect the catalytic activity and coke formation.

Keywords

• Mixed oxides
• Nickel exsolution
• Biogas valorization
• Alternative synthesis methodologies