Silicalite-1 Layer Secures the Bifunctional Nature of a CO Hydrogenation Catalyst.

Close proximity usually shortens the travel distance of reaction intermediates, thus able to promote the catalytic performance of CO hydrogenation by a bifunctional catalyst, such as the widely reported InO/H-ZSM-5. However, nanoscale proximity (, powder mixing, PM) more likely causes the fast deactivation of the catalyst, probably due to the migration of metals (, In) that not only neutralizes the acid sites of zeolites but also leads to the reconstruction of the InO surface, thus resulting in catalyst deactivation. Additionally, zeolite coking is another potential deactivation factor when dealing with this methanol-mediated CO hydrogenation process.

Detecting Cage Crossing and Filling Clusters of Magnesium and Carbon Atoms in Zeolite SSZ-13 with Atom Probe Tomography.

The conversion of methanol to valuable hydrocarbon molecules is of great commercial interest, as the process serves as a sustainable alternative for the production of, for instance, the base chemicals for plastics. The reaction is catalyzed by zeolite materials. By the introduction of magnesium as a cationic metal, the properties of the zeolite, and thereby the catalytic performance, are changed.

Operando Laboratory-Based Multi-Edge X-Ray Absorption Near-Edge Spectroscopy of Solid Catalysts.

Laboratory-based X-ray absorption spectroscopy (XAS) and especially X-ray absorption near-edge structure (XANES) offers new opportunities in catalyst characterization and presents not only an alternative, but also a complementary approach to precious beamtime at synchrotron facilities. We successfully designed a laboratory-based setup for performing operando, quasi-simultaneous XANES analysis at multiple K-edges, more specifically, operando XANES of mono-, bi-, and trimetallic CO hydrogenation catalysts containing Ni, Fe, and Cu. Detailed operando XANES studies of the multielement solid catalysts revealed metal-dependent differences in the reducibility and re-oxidation behavior and their influence on the catalytic performance in CO hydrogenation.

New insights into the NH-selective catalytic reduction of NO over Cu-ZSM-5 as revealed by spectroscopy.

To control diesel vehicle NO emissions, Cu-exchanged zeolites have been applied in the selective catalytic reduction (SCR) of NO using NH as reductant. However, the harsh hydrothermal environment of tailpipe conditions causes irreversible catalyst deactivation. The aggregation of isolated Cu brings about unselective ammonia oxidation along with the main NH-SCR reaction.

Favoring the Methane Oxychlorination Reaction over EuOCl by Synergistic Effects with Lanthanum.

The direct conversion of CH into fuels and chemicals produces less waste, requires smaller capital investments, and has improved energy efficiency compared to multistep processes. While the methane oxychlorination (MOC) reaction has been given little attention, it offers the potential to achieve high CH conversion levels at high selectivities. In a continuing effort to design commercially interesting MOC catalysts, we have improved the catalyst design of EuOCl by the partial replacement of Eu by La.