We present a study of stepwise cryogenic N adsorption on size-selected Fe (n = 8-20) clusters within a hexapole collision cell held at T = 21-28 K. The stoichiometries of the observed adsorption limits and the kinetic fits of stepwise N uptake reveal cluster size-dependent variations that characterize four structural regions. Exploratory density functional theory studies support tentative structural assignment in terms of icosahedral, hexagonal antiprismatic, and closely packed structural motifs. There are three particularly noteworthy cases, Fe with a peculiar metastable adsorption limit, Fe with unprecedented nitrogen phobia (inefficient N adsorption), and Fe with an isomeric mixture that undergoes relaxation upon considerable N uptake.
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http://dx.doi.org/10.1063/5.0064965 | DOI Listing |
Nanoscale
November 2024
Aix Marseille Univ, CNRS, CINAM, Marseille, France.
The adsorption of CO and oxygen and CO oxidation on size-selected Pt clusters were studied by indirect nanoplasmonic sensing (INPS) in the pressure range of 1-100 Pa at = 418 K. CO adsorption was reversible, inducing a blue-shift in the localised surface plasmon resonance (LSPR) response, regardless of the initial CO pressure. We observe a plateau at approximately Δ = -0.
View Article and Find Full Text PDFJ Chem Phys
October 2023
Department of Chemistry and State Research Center OPTIMAS, Rheinland-Pfälzische Technische Universität (RPTU) Kaiserslautern-Landau, 67663 Kaiserslautern, Germany.
We present an IR-PD study of tantalum cluster adsorbate complexes [Tan(N2)m]+, abbreviated (n,m), n = 5-8. We utilize infrared spectroscopy of isolated and size selected clusters as prepared and characterized by a cryogenic tandem ion trap setup, and we augment our experiments with quantum chemical simulations at the level of density functional theory. The cluster adsorbate complexes (n,m) reveal vibrational bands above 2000 cm-1, which indicate end-on coordinated μ1-N2 oscillators, and bands below 2000 cm-1, which indicate side-on μ2-κN:κN,N coordinated ones.
View Article and Find Full Text PDFJ Chem Phys
October 2023
Department of Chemistry and State Research Center OPTIMAS, Rheinland-Pfälzische Technische Universität (RPTU) Kaiserslautern-Landau, 67663 Kaiserslautern, Germany.
We investigate small tantalum clusters Tan+, n = 2-4, for their capability to cleave N2 adsorption spontaneously. We utilize infrared photon dissociation (IR-PD) spectroscopy of isolated and size selected clusters under cryogenic conditions within a buffer gas filled ion trap, and we augment our experiments by quantum chemical simulations (at DFT level). All Tan+ clusters, n = 2-4, seem to cleave N2 efficiently.
View Article and Find Full Text PDFSci Rep
October 2023
Chemistry Department, Faculty of Science, Assiut University, Assiut, 71516, Egypt.
For the first time, covalently anchoring size selected silver nanoclusters [Ag(MNBA)] on the BiS@UiO-66-NH and MoS@UiO-66-NH heterojunctions were constructed as novel photocatalysts for photodegradation of methylene blue (MB) dye. The anchoring of Ag on MoS@UiO-66-NH and BiS@UiO-66-NH heterojunctions extended the light absorption of UiO-66-NH to the visible region and improved the transfer and separation of photogenerated charge carriers through the heterojunctions with a unique band gap structure. The UV-Vis-NIR diffuse reflectance spectroscopic analysis confirmed that the optical absorption properties of the UiO-66-NH were shifted from the UV region at 379 nm to the visible region at ~ 705 nm after its doping with BiS nanorods and Ag nanoclusters (BiS@UiO-66-NH-S-Ag).
View Article and Find Full Text PDFPhys Chem Chem Phys
April 2023
Science Program, Texas A&M University, Education City, Doha, Qatar.
Recycling CO back to fuels offers an ideal solution to control anthropogenic global CO emissions as well as providing a sustainable green solution to alternative energy resources from a cheap and earth-abundant carbon source. Size-selected nanoclusters open a novel area in catalysis as these atomically precise nanoclusters possess unique electronic and catalytic properties different from larger nanoparticles and traditional bulk catalysts. In this work, we have investigated the ability of first-row transition metal nanoclusters (Sc-Cu) of varying sizes (3 to 10 atoms) for CO electroreduction (CORR).
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