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Heterogeneous single‐metal‐site catalysts usually suffer from poor stability, thereby limiting industrial applications. Dual Pd1−Ru1 single‐atom‐sites supported on porous ionic polymers (Pd1−Ru1/PIPs) were constructed using a wetness impregnation method. The two isolated metal species in the form of a binuclear complex were immobilized on the cationic framework of PIPs through ionic bonds. Compared to the single Pd‐ or Ru‐site catalyst, the dual single‐atom system exhibits higher activity with 98 % acetylene conversion and near 100 % selectivity to dialkoxycarbonylation products, as well as better cycling stability for ten cycles without obvious decay. Based on DFT calculations, it was found that the single‐Ru site exhibited a strong CO adsorption energy of −1.6 eV, leading to an increase in the local CO concentration of the catalyst. Notably, the Pd1−Ru1/PIPs catalyst had a much lower energy barrier of 2.49 eV compared to 3.87 eV of Pd1/PIPs for the rate‐determining step. The synergetic effect between neighboring single sites Pd1 and Ru1 not only enhanced the overall activity, but also stabilized PdII active sites. The discovery of synergetic effects between single sites can deepen our understanding of single‐site catalysts at the molecular level. [ABSTRACT FROM AUTHOR]

Active Zn species in Cu‐based methanol synthesis catalysts have not been clearly identified yet due to their complex nature and dynamic structural changes during reactions. Herein, atomically dispersed Zn on ZrO2 support is established in Cu‐based catalysts by separating Zn and Zr components from Cu (Cu−ZnZr) via the double‐nozzle flame spray pyrolysis (DFSP) method. It exhibits superiority in methanol selectivity and yield compared to those with Cu−ZnO interface and isolated ZnO nanoparticles. Operando X‐ray absorption spectroscopy (XAS) reveals that the atomically dispersed Zn species are induced during the reaction due to the strengthened Zn−Zr interaction. They can suppress formate decomposition to CO and decrease the H2 dissociation energy, shifting the reaction to methanol production. This work enlightens the rational design of unique Zn species by regulating coordination environments and offers a new perspective for exploring complex interactions in multi‐component catalysts. [ABSTRACT FROM AUTHOR]

Pd/ZnO catalysts show good activity and high selectivity to methanol during catalytic CO2 hydrogenation. The Pd‐Zn alloy phase has usually been considered as the active phase, though mechanistic studies under operando conditions have not been conducted to verify this. Here, we report a mechanistic study under realistic conditions of methanol synthesis, using in situ and operando X‐ray absorption spectroscopy, X‐ray powder diffraction, and time‐resolved isotope labeling experiments coupled with FTIR spectroscopy and mass spectrometry. Pd‐Zn alloy‐based catalysts, prepared through reduction of a heterobimetallic PdIIZnII acetate bridge complex, and which do not contain zinc oxide or any PdZn/ZnO interface, produce mostly CO. The Pd‐Zn phase is associated with the formation of CO, and does not provide the active sites required to produce methanol from the direct hydrogenation of carbon dioxide. The presence of a ZnO phase, in contact with a Pd‐Zn phase, is essential for efficient methanol production. [ABSTRACT FROM AUTHOR]

Abstract: Grafting Ti(=NtBu)(Me2Pyr)2(py)2 (Me2Pyr= 2,5‐dimethylpyrrolyl, py=pyridine) onto the surface of silica partially dehydroxylated at 700 °C gives the well‐defined silica‐supported Ti imido complex (≡SiO)Ti(=NtBu)(Me2Pyr)(py)2, which is fully characterized by IR and solid‐state NMR spectroscopy as well as elemental and mass balance analyses. While stoichiometric imido‐transfer reactivity is typical for Ti imides, the obtained surface complex is unique in that it enables catalytic transformations involving Ti imido and oxo intermediates. In particular, it efficiently catalyzes imidation of carbonyl compounds with N‐sulfinylamines by oxo/imido heterometathesis. [ABSTRACT FROM AUTHOR]

C4 olefin separations present one of the great challenges in hydrocarbon purifications owing to their similar structures, thus a single separation mechanism often met with limited success. Herein we report a series of anion-pillared interpenetrated copper coordination for which the cavity and functional site disposition can be varied in 0.2 Å scale increments by altering the anion pillars and organic linkers (GeFSIX-2-Cu-i (ZU-32), NbFSIX-2-Cu-i (ZU-52), GeFSIX-14-Cu-i (ZU-33)), which enable selective recognition of different C4 olefins. In these materials the rotation of the organic linkers is controlled to create a contracted flexible pore window that enables the size-exclusion of specific C4 olefins, while still adsorbing significant amounts of 1,3-butadiene (C4H6) or 1-butene (n-C4H8). Combining the molecular recognition and size-sieving effect, these materials unexpectedly realized the sieving of C4H6/n-C4H8, C4H6/iso-C4H8, and n-C4H8/iso-C4H8 with high capacity. [ABSTRACT FROM AUTHOR]

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The article discusses research on the use of X-ray absorption near-edge structure (XANES) spectroscopy and density functional theory (DFT) calculations in analyzing the amorphous structure of titanium dioxide-supported molybdenum oxide catalysts. It outlines the methodology followed in examining the catalyst structure. Details of the experimental and calculated XANES spectra recorded for ammonium heptamolybdate are presented, noting intensity ratio of resonances that characterize the spectra.

Deprotonierung einer Base: Mithilfe von hochauflösender Elektronenenergieverlust ‐ Spektroskopie und Hochvakuum ‐ Infrarotspektroskopie wurde nachgewiesen, dass bei hoher Oberflächenbelegung von ZnO ‐ Einkristallen oder ‐ Nanopartikeln mit Ammoniak ein Protonentransfer von diesem Adsorbat auf Sauerstoffatome der Oberfläche stattfinden kann (siehe Bild; Zn blaue Stäbe, O rot, N blaue Kugeln, H gelb). Die Ergebnisse von DFT ‐ Rechnungen stützen diese Beobachtung. [ABSTRACT FROM AUTHOR]