Trimetallic Catalyst Configuration for Syngas Production

Abstract

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 -reoxidizedthat 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 À 1 kg cat À 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 À 1 kg cat À 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 2reoxidation 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.

Mixed oxides as multi-functional reaction media for chemical looping catalysis

“…An extensively investigated topics is methane to syngas/H 2 conversion. 95,[109][110][111][112][113][114][115][116][117]123,[125][126][127]130,136,185,[193][194][195][196][197][198][199][200][201][202][203][204][205][206][207][208] A few other studies explored a phase transition sorbent concept where a single mixed oxide particle combines the function of a redox oxide (for oxygen separation), a carbonate sorbent (for CO 2 separation), and a catalyst (to catalyze chemical reactions). 95,123,130,197,198,[209][210][211] For instance, a recent study adopted the chemical looping strategy to selectively oxidize ammonia with excellent NO selectivity for nitric acid production.…”