Trimetallic catalyst configuration for syngas production

Dry reforming of methane (DRM) is a promising catalytic process for syngas production, utilizing and transforming CO2 to higher density compounds in view of circular economy. The performance of a bimetallic NiFe/MgAl2O4 strongly depends on the initial catalyst state - calcined, reduced or CO2-reoxidized - that corresponds to different structures and is for each state significantly improved by the addition of a low Rh concentration (similar to 1 wt%). In the bimetallic catalyst, reduction is required to form the most active phase, a Ni3Fe alloy, showing a CH4 consumption rate of 0.9 mol s(-1) kg(cat)(-1). For the trimetallic NiFeRh, the effect of the initial state is less pronounced, yielding a CH4 consumption rate of 2.4 mol s(-1) kg(cat)(-1) after CO2-reoxidation. Advanced characterization and modelling were used to gain insights in the trimetallic system and to systematically assess the role of each element. In NiFeRh, reduction leads to the formation of a trimetallic alloy. A subsequent CO2-reoxidation induces partial Fe segregation from the trimetallic alloy, leading to separate Fe3O4. The latter structure represents the most active state due to the double role that the trimetallic catalyst takes up after H-2-reduction and CO2-reoxidation: improved activity due to highly dispersed NiRh and NiFe alloy particles and carbon removal due to Fe3O4 particles