Influence of aluminium distribution on the diffusion mechanisms and pairing of [Cu(NH)] complexes in Cu-CHA.

The performance of Cu-exchanged chabazite (Cu-CHA) for the ammonia-assisted selective catalytic reduction of NO (NH-SCR) depends critically on the presence of paired complexes. Here, a machine-learning force field augmented with long-range Coulomb interactions is developed to investigate the effect of Al-distribution and Cu-loading on the mobility and pairing of complexes. Performing unbiased and constrained molecular dynamics simulations, we obtain unique information inaccessible to first-principle calculations and experiments.

Effect of SO and SO Exposure to Cu-CHA on Surface Nitrate and NO Formation for NH-SCR.

We report effects of SO and SO exposure on ammonium nitrate (AN) and NO formation in Cu-CHA used for NH-SCR. First-principles calculations and several characterizations (ICP, BET, XRD, UV-vis-DRS) were applied to characterize the Cu-CHA material and speciation of sulfur species. The first-principles calculations demonstrate that the SO exposure results in both (bi)sulfite and (bi)sulfate whereas the SO exposure yields only (bi)sulfate.

Interpretation of H-TPR from Cu-CHA Using First-Principles Calculations.

Temperature-programmed reduction and oxidation are used to obtain information on the presence and abundance of different species in complex catalytic materials. The interpretation of the temperature-programmed reaction profiles is, however, often challenging. One example is H temperature-programmed reduction (H-TPR) of Cu-chabazite (Cu-CHA), which is a material used for ammonia assisted selective catalytic reduction of NO (NH-SCR).

Surfactant-Free Colloidal Syntheses of Gold-Based Nanomaterials in Alkaline Water and Mono-alcohol Mixtures.

Gold nanoparticles (Au NPs) and gold-based nanomaterials combine unique properties relevant for medicine, imaging, optics, sensing, catalysis, and energy conversion. While the Turkevich-Frens and Brust-Schiffrin methods remain the state-of-the-art colloidal syntheses of Au NPs, there is a need for more sustainable and tractable synthetic strategies leading to new model systems. In particular, stabilizers are almost systematically used in colloidal syntheses, but they can be detrimental for fundamental and applied studies.