Alloyed molybdenum enables efficient alcohol hydrodeoxygenation with supported bimetallic catalysts.

Bimetallic heterogeneous catalysts combining group 9 metals (Rh, Ir) or group 10 metals (Ni, Pd, Pt) with Mo on a silica-based support have been synthesized surface organometallic chemistry and assessed in their catalytic activity for the hydrodeoxygenation (HDO) of alcohols with particular emphasis on the structural evolution of the catalysts and the role of Mo. The investigation was conducted with an air-free approach to isolate any sample alterations exclusively to those caused by the reaction. Structural analysis was performed using a combination of (S)TEM, IR, and XAS.

Mn-promoted MoS catalysts for CO hydrogenation: enhanced methanol selectivity due to MoS/MnO interfaces.

Considering the alarming scenario of climate change, CO hydrogenation to methanol is considered a key process for phasing out fossil fuels by means of CO utilization. In this context, MoS catalysts have recently shown to be promising catalysts for this reaction, especially in the presence of abundant basal-plane sulfur vacancies and due to synergistic mechanisms with other phases. In this work, Mn-promoted MoS prepared by a hydrothermal method presents considerable selectivity for CO hydrogenation to methanol in comparison with pure MoS and other promoters such as K and Co.

Group 10 Metal Allyl Amidinates: A Family of Readily Accessible and Stable Molecular Precursors to Generate Supported Nanoparticles.

The synthesis of well-defined materials as model systems for catalysis and related fields is an important pillar in the understanding of catalytic processes at a molecular level. Various approaches employing organometallic precursors have been developed and established to make monodispersed supported nanoparticles, nanocrystals, and films. Using rational design principles, a new family of precursors based on group 10 metals suitable for the generation of small and monodispersed nanoparticles on metal oxides has been developed.

Active Site Descriptors from Mo NMR Signatures of Silica-Supported Mo-Based Olefin Metathesis Catalysts.

The olefin metathesis activity of silica-supported molybdenum oxides depends strongly on metal loading and preparation conditions, indicating that the nature and/or amounts of the active sites vary across compositionally similar catalysts. This is illustrated by comparing Mo-based (pre)catalysts prepared by impregnation (2.5-15.

Solution-Processed CuS Nanostructures for Solar Hydrogen Production.

CuS is a promising solar energy conversion material due to its suitable optical properties, high elemental earth abundance, and nontoxicity. In addition to the challenge of multiple stable secondary phases, the short minority carrier diffusion length poses an obstacle to its practical application. This work addresses the issue by synthesizing nanostructured CuS thin films, which enables increased charge carrier collection.

Ultrahigh Mass Activity Pt Entities Consisting of Pt Single atoms, Clusters, and Nanoparticles for Improved Hydrogen Evolution Reaction.

Platinum is one of the best-performing catalysts for the hydrogen evolution reaction (HER). However, high cost and scarcity severely hinder the large-scale application of Pt electrocatalysts. Constructing highly dispersed ultrasmall Platinum entities is thereby a very effective strategy to increase Pt utilization and mass activities, and reduce costs.

Selective ligand exchange synthesis of Au(2-PET) from Au(SG).

Replacement of protecting ligands of gold nanoclusters by ligand exchange has become an established post-synthetic tool for selectively modifying the nanoclusters' properties. Several Au nanoclusters are known to additionally undergo size transformations upon ligand exchange, enabling access to cluster structures that are difficult to obtain by direct synthesis. This work reports on the selective size transformation of Au(SG) (SG: glutathione) nanoclusters to Au(2-PET) (2-PET: 2-phenylethanethiol) nanoclusters through a two-phase ligand exchange process at room temperature.

The Dynamic Structure of Au(SR) Nanoclusters Supported on CeO upon Pretreatment and CO Oxidation.

Atomically precise thiolate protected Au nanoclusters Au(SCHPh) on CeO were used for in-situ (operando) extended X-ray absorption fine structure/diffuse reflectance infrared fourier transform spectroscopy and ex situ scanning transmission electron microscopy-high-angle annular dark-field imaging/X-ray photoelectron spectroscopy studies monitoring cluster structure changes induced by activation (ligand removal) and CO oxidation. Oxidative pretreatment at 150 °C "collapsed" the clusters' ligand shell, oxidizing the hydrocarbon backbone, but the S remaining on Au acted as poison. Oxidation at 250 °C produced bare Au surfaces by removing S which migrated to the support (forming Au-S), leading to highest activity.

Ligand Migration from Cluster to Support: A Crucial Factor for Catalysis by Thiolate-protected Gold Clusters.

Thiolate protected metal clusters are valuable precursors for the design of tailored nanosized catalysts. Their performance can be tuned precisely at atomic level, e. g.

On the mechanism of rapid metal exchange between thiolate-protected gold and gold/silver clusters: a time-resolved in situ XAFS study.

The fast metal exchange reaction between Au and AgAu nanoclusters in solution at -20 °C has been studied by in situ X-ray absorption spectroscopy (time resolved quick XAFS) in transmission mode. A cell was designed for this purpose consisting of a cooling system, remote injection and mixing devices. The capability of the set-up is demonstrated for second and minute time scale measurements of the metal exchange reaction upon mixing Au/toluene and AgAu/toluene solutions at both Ag K-edge and Au L-edge.