Trimetallic Catalyst Configuration for Syngas Production

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Dry reforming of methane (DRM) is a promising catalytic process for syngas production, utilizing and transforming CO 2 to higher density compounds in view of circular economy. The performance of a bimetallic NiFe/MgAl 2 O 4 strongly depends on the initial catalyst state – calcined, reduced or CO 2 ‐reoxidized – that corresponds to different structures and is for each state significantly improved by the addition of a low Rh concentration (∼1 wt%). In the bimetallic catalyst, reduction is required to form the most active phase, a Ni 3 Fe alloy, showing a CH 4 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 CH 4 consumption rate of 2.4 mol s −1 kg cat −1 after CO 2 ‐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 CO 2 ‐reoxidation induces partial Fe segregation from the trimetallic alloy, leading to separate Fe 3 O 4 . The latter structure represents the most active state due to the double role that the trimetallic catalyst takes up after H 2 ‐reduction and CO 2 ‐reoxidation: improved activity due to highly dispersed NiRh and NiFe alloy particles and carbon removal due to Fe 3 O 4 particles.