Aram L. Bugaev

Aram L. Bugaev
Southern Federal University | sfedu · The Smart Materials Research Institute

PhD in Physics and Chemistry

About

103
Publications
22,955
Reads
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1,422
Citations
Introduction
- Synthesis and characterization of novel materials for catalysis, energy, gas separation and storage, bio-medical applications, etc. - Synchrotron-based research - Application of in situ and operando experiments for structure-activity determination in metal nanoparticles, MOFs, zeolites and many other materials. - Development of advanced methods for XANES and EXAFS analysis - Computer modelling of atomic and electronic properties of materials
Additional affiliations
November 2014 - present
Università degli Studi di Torino
Position
  • PhD Student
February 2014 - August 2015
Southern Federal University
Position
  • Assistant
October 2011 - September 2012
Deutsches Elektronen-Synchrotron
Position
  • Researcher
Education
September 2012 - July 2014
Southern Federal University
Field of study
  • Physics
September 2008 - July 2012
Southern Federal University
Field of study
  • Physics

Publications

Publications (103)
Article
We report an in situ, temperature and H2 pressure-dependent, characterization of (2.6  0.4) nm palladium nanoparticles supported on active carbon during the process of hydride phase formation. For the first time the core-shell structure is highlighted in the single-component particles on the basis of a different atomic structure and electronic con...
Article
Accurate modeling of the X-ray absorption near-edge spectra (XANES) is required to unravel the local structure of metal sites in complex systems and their structural changes upon chemical or light stimuli. Two relevant examples are reported here concerning the following: (i) the effect of molecular adsorption on 3d metals hosted inside metal?organi...
Article
Palladium nanoparticles (NPs) find numerous applications as catalysts for hydrogenation of hydrocarbons. Under reaction conditions, formation of palladium hydrides and carbides may occur, which affects the catalytic properties of the catalyst. Unlike pure hydride phase, whose phase diagram is well-studied, conditions of formation of palladium carbi...
Article
Full-text available
The selective activation of inert C–H bonds has emerged as a promising tool for avoiding the use of wasteful traditional coupling reactions. Oxidative coupling of simple aromatics allows for a cost-effective synthesis of biaryls. However, utilization of this technology is severely hampered by poor regioselectivity and by the limited stability of st...
Article
Recently, a reaction sequence was developed for the production of tricarballylic acid, an interesting plasticiser precursor, from citric acid by using a H-Beta zeolite and Pd/C catalyst. Although yields of 85% of tricarballylic acid were obtained, citric acid elicited Al leaching from the zeolite framework, resulting in loss of activity. In this wo...
Article
Full-text available
The production of carbon-rich hydrocarbons via CO2 valorization is essential for the transition to renewable, non-fossil-fuel-based energy sources. However, most of the recent works in the state of the art are devoted to the formation of olefins and aromatics, ignoring the rest of the hydrocarbon commodities that, like propane, are essential to our...
Article
Modern synchrotron radiation sources and free electron laser made X-ray absorption spectroscopy (XAS) an analytical tool for the structural analysis of materials under in situ or operando conditions. Fourier approach applied to the extended region of the XAS spectrum (EXAFS) allows the estimation of the number of structural and non-structural param...
Article
A series of micro-mesoporous materials with nanosponge structure were synthesized in accelerated mode. The influence of the perchlorate oxyanion promoter on the materials characteristics was thoroughly investigated. It was shown that the formation of nanosponge structure with high amount of promoter occurs through the consecutive steps that can be...
Article
Oxide-derived Cu materials are most commonly used as electrocatalysts for the carbon dioxide reduction reaction (CO2RR). Previous studies have proved that Cu⁺ and residual subsurface oxygen species can enhance the CO2RR activity; however the stable presence of Cu⁺ remains a subject of debate. Here, we design a strategy of single-atom Sn anchored on...
Article
Heterogeneous single-site catalysts contain spatially isolated, well-defined active sites. This allows not only their easy recovery by solid-liquid separation, but also the detailed active site design like in homogeneous catalysts. Here, heterogeneous Pd(II) single-site catalysts were assembled, based on mesoporous metal oxide-bisphosphonate materi...
Article
Evolution of surface and bulk palladium oxides in supported palladium nanoparticles was followed in situ using X-ray absorption spectroscopy. The surface oxide was found to be easily reducible in hydrogen at room temperature, while removal of bulk oxide required heating in hydrogen above 100 °C. We also found that the co-presence of hydrogen and ox...
Article
Full-text available
Adsorption of ethylene on palladium, a key step in various catalytic reactions, may result in a variety of surface-adsorbed species and formation of palladium carbides, especially under industrially relevant pressures and temperatures. Therefore, the application of both surface and bulk sensitive techniques under reaction conditions is important fo...
Article
A series of unsupported mono- and bimetallic MonW12-nS2 catalysts were synthesized by alumina elimination from supported MonW12-nS2/Al2O3 samples using acid etching. Alumina supported catalysts have been in turn prepared by using monometallic H4SiMo12O40 and H4SiW12O40 heteropolyacids (HPAs), their mixture with Mo/W atomic ratio equal to 1/11 and 3...
Article
Hydrodeoxygenation (HDO) of sugar alcohols could be a valuable reaction for the renewable production of alkenes. However, reports on deoxygenation of longer polyols (e.g. erythritol, xylitol, sorbitol) to mono-alkenes are scarce, especially when using H2 as reducing agent. Here we design a conceptually different catalyst system for polyol conversio...
Article
Full-text available
The formation of palladium hydrides is a well-known phenomenon, observed for both bulk and nanosized samples. The kinetics of hydrogen adsorption/desorption strongly depends on the particle size and shape, as well as the type of support and/or coating of the particles. In addition, the structural properties of hydride phases and their distribution...
Article
A challenge in converting CO2 into hydrocarbons (HC) via methanol (MeOH) is the gap between the optimal temperature for each step (i.e. ≤250 °C for MeOH and ≥350 °C for HC). The focus of this study is to elucidate the cause of the limitations associated to oxygenate and hydrocarbon formation in combined PdZn and H-ZSM-5 catalysts at 250 to 350 °C....
Article
Heterogeneous single-site catalysts can combine the precise active site design of organometallic complexes with the efficient recovery of solid catalysts. Based on recent progress on homogeneous thioether ligands for Pd-catalyzed C-H activation reactions, we here develop a scalable MOF-based heterogeneous single-site catalyst containing S,O-moietie...
Article
Lithium-excess disordered rock-salt oxides have opened up a new vista in search of high-capacity cathodes, resulting in a variety of new materials with versatile elemental compositions. This work introduces W⁶⁺ as a possible charge-compensator and explores the solid-solution series Li1+x/100Ni1/2−x/120Ti1/2−x/120Wx/150O2 (x = 0, 5, 10, 15, 20), whi...
Article
Full-text available
Element selectivity and possibilities for in situ and operando applications make X-ray absorption spectroscopy a powerful tool for structural characterization of catalysts. While determination of coordination numbers and interatomic distances from extended spectral region is rather straightforward, analysis of X-ray absorption near-edge structure (...
Article
Palladium-based catalysts are exploited in the industrial scale for selective hydrogenation of hydrocarbons. Formation of palladium carbide and hydride phases under reaction conditions changes the catalytic properties of the material, which points to the importance of operando characterization for determining a relation between the relative fractio...
Article
Full-text available
Transition-metal-doped carbon catalysts are promising Pt-free alternatives for low-temperature fuel cells. They are frequently obtained from sacrificial N-rich zeolitic imidazolate frameworks (ZIFs) doped with Co and Fe. The optimal low loading of metals has to be achieved to guarantee the competitive efficiency and facilitate an inquiry into the m...
Article
Full-text available
We report a series of Pd K-edge and Pt L3-edge X-ray absorption spectra (XAS) collected in situ during thermal treatment of functionalized UiO-67-Pd and UiO-67-Pt metal-organic frameworks in inert and reducing atmospheres. We present raw synchrotron data from three subsequent experiments at different beamlines, normalized XAS spectra and k2-weighte...
Article
Heteroatom-doped carbon materials (HDCM) are perspective Pt-free alternatives for applications in fuel cells. The Fe,Co,Zn-N/C catalysts were obtained by pyrolysis (at 700 °C in Ar) of sacrificial bimetallic zeolitic imidazolate frameworks (Co,Zn-ZIF), prepared with different Co/Zn ratio by a microwave-assisted solvothermal synthesis (at 140 °C in...
Article
In this work we have applied machine learning methods (Extra Trees, Ridge Regression and Neural Networks) to predict structural parameters of the system based on its XANES spectrum. We used two ML approaches: direct one, i.e. when ML model is trained to predict the structural parameters directly from the XANES spectrum and inverse one when ML model...
Article
Functionalization of metal-organic frameworks (MOFs) with noble metals is a promising way for producing new versatile catalysts that will combine the outstanding porosity and specific surface area of MOFs with high catalytic activity of metals. Here, we present a comparative study of two metal-organic frameworks with UiO-67 topology, functionalized...
Article
The process of desorption of hydrogen from small palladium nanoparticles is monitored by time-resolved synchrotron X-ray diffraction. Changes in the diffraction patterns corresponding to the transition from the palladium β-phase to the α-phase are detected with an accuracy of 0.3 s. The model of the continuous change in the size of the β-phase regi...
Article
Full-text available
We report the series of Pd K-edge X-ray absorption spectra collected during hydrogenation of ethylene with variable ethylene/hydrogen ratio over carbon supported palladium nanoparticles. The data presented in this article includes normalized X-ray absorption spectra, k ² -weighted oscillatory χ(k)functions extracted from the extended X-ray absorpti...
Article
We present a detailed extended X-ray absorption fine structure (EXAFS) characterization of the formation process of palladium nanoparticles (NPs) inside UiO-67 metal-organic framework (MOF). Starting from the initial UiO-67 structure with 10% of PdCl2bpydc moieties with grafted Pd ions replacing standard 4,4′-biphenyldicarboxylate linkers, we follo...
Article
We describe the synthesis and corresponding full characterization of the set of UiO-66 metal-organic frameworks (MOFs) with 1,4-benzenedicarboxylate (C6H4(COOH)2, hereafter H2BDC) and 1,4-naphthalenedicarboxylate (C10H6(COOH)2, hereafter H2NDC) mixed linkers with NDC contents of 0, 25, 50, and 100%. Their structural (powder X-ray diffraction, PXRD)...
Article
Palladium-based catalysts are widely applied for the selective hydrogenation of acetylene in acetylene/ethylene mixtures. Under reaction conditions, palladium hydride or carbide phases can be formed, which change the catalytic properties of material. In the current work, we focus on the process of carbide phase formation in supported palladium nano...
Article
In the last decade the appearance of progressively more sophisticated codes, together with the increased computational capabilities, has made XANES a spectroscopic technique able to quantitatively confirm (or discard) a structural model, thus becoming a new fundamental diagnostic tool in catalysis, where the active species are often diluted metal c...
Article
Formation of gold nanoparticles (NPs) from the mixture containing NaAuCl4 as a precursor, octadecene as a solvent and oleylamine as a reducing agent was studied in situ by means of optical and X-ray spectroscopies. Dynamic light scattering (DLS) revealed the presence of initial aggregates of 500 nm average size which split into nanoparticles of abo...
Article
Full-text available
Magnetic nanoparticles (MNPs) made of iron oxides with cubic symmetry (Fe 3 O 4 , γ -Fe 2 O 3 ) are demanded objects for multipurpose in biomedical applications as contrast agents for magnetic resonance imaging, magnetically driven carriers for drug delivery, and heaters in hyperthermia cancer treatment. An optimum balance between the right particl...
Article
After a short introduction highlighting the potentialities of metal–organic frameworks (MOFs) and the power of X-ray absorption spectroscopies (XAS), a list of selected examples follows. The first part of this review provides the basic concepts that are behind the most used XAS techniques: Extended X-ray Absorption Fine Structure (EXAFS) and X-ray...
Article
Full-text available
A setup for fluorescence-detected X-ray absorption spectroscopy (XAS) with sub-second time resolution has been developed. This technique allows chemical speciation of low-concentrated materials embedded in highly absorbing matrices, which cannot be studied using transmission XAS. Using this setup, the reactivity of 1.5 wt% Pt/CeO 2 catalyst was stu...
Article
Experimental technique for preparing of space arranged arrays of bimetallic AuAg nanoparticles in the near-surface region of glass, exhibiting surface plasmon resonance (SPR) characteristics varying in the wider ranges comparing to monometallic Au, Ag particles or corresponding thin films, is presented together with the structural characterization...
Article
The behaviour of a Pd(OAc)2/P4VP catalyst submitted to different pre-treatments (pre-reduced, pre-oxidised and un-treated) during the aerobic oxidation of 2-propanol to acetone in the gas phase has been investigated. Synchronous, time-resolved, SAXS/XAS/MS techniques coupled with operando DRIFT spectroscopy (which gave information on the destiny of...
Article
Full-text available
The Pb(Zr0.56Ti0.44)O3 (PZT) ceramics was subjected to a pressure-induced activation at 320 MPa in a Bridgman anvil, where a load pressure was combined with a shear deformation. The induced changes in the linear and angular parameters of a unit cell, in the ratio of coexisting rhombohedral (R3m) and tetragonal (P4mm) phases as well as in the dielec...
Article
A set of Sm-doped iron oxide magnetic nanoparticles (FexOy NPs) of different size was synthesized by means of microware-assisted methods. Powder X-ray diffraction and transmission electron microscopy showed FexOy NPs with inverse spinel structure and high number of defects which are typical for small NPs. Mössbauer and X-ray absorption spectroscopy...
Article
The presence of a core/shell behavior in Pd nanoparticles (NPs) during the formation of the metal- hydride phase has recently been highlighted combining X-ray absorption and scattering experiments [J. Phys. Chem. C 2017, 121, 18202]. In this work, we focus on formation of the carbide phase in the bulk region and on the surface of supported palladiu...
Article
Full-text available
The size and shape distribution of metal nanoparticles (NPs) are important parameters that need to be tuned in order to achieve desired properties of materials for practical applications. In the current work, we present the synthesis of palladium NPs supported on silica by three different methods, applying reduction by sodium borohydride, hydrazine...
Article
A heteroatom-doped carbon-based electrocatalyst for the oxygen reduction reaction (ORR) was prepared from a hybrid zeolitic imidazolate framework (ZIF) using a step-by-step approach. A bimetallic Co,Zn-ZIF was synthesized by a microwave-assisted method and then enriched with Fe and N. The resulting ZIF was pyrolysed at 700 °C in an inert atmosphere...
Article
Functionalization of metal-organic frameworks with metal nanoparticles (NPs) is a promising way for producing advanced materials for catalytic applications. We present synthesis and in situ characterization of palladium NPs encapsulated inside functionalized UiO-67 metal-organic framework. The initial structure was synthesized with 10% of PdCl2bpyd...
Article
Formation of palladium hydride and carbide phases in palladium-based catalysts is a critical process which changes the catalytic performance and selectivity of the catalysts in important industrial reactions, such as selective hydrogenation of alkynes or alkadienes. We present a comprehensive study of a 5 wt.% carbon supported Pd nanoparticles (NPs...
Chapter
The first part of this chapter provides a simple, but general, description on the physical phenomena that are behind the interaction of probe beams (photons, electrons, or neutrons) with condensed matter. The differences in penetration depth, de Broglie wavelength, and requested sample environment for the three kinds of beams are stressed. The diff...