Umeå University's logo

umu.sePublikasjoner
Endre søk
Link to record
Permanent link

Direct link
Klechikov, Alexey
Alternativa namn
Publikasjoner (10 av 22) Visa alla publikasjoner
Rebrikova, A. T., Klechikov, A., Iakunkov, A., Sun, J., Talyzin, A. V., Avramenko, N. V. & Korobov, M. (2020). Swollen Structures of Brodie Graphite Oxide as Solid Solvates. The Journal of Physical Chemistry C, 124(42), 23410-23418
Åpne denne publikasjonen i ny fane eller vindu >>Swollen Structures of Brodie Graphite Oxide as Solid Solvates
Vise andre…
2020 (engelsk)Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 124, nr 42, s. 23410-23418Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Swelling of Brodie graphite oxide (B-GO) was studied for a series of normal alcohols from methanol to 1-nonanol. Isopiestic, X-ray diffraction (XRD), thermogravimetric, and differential scanning calorimetry data demonstrated that sorption of polar liquids into GO lamellas formed the set of regular swollen structures, simple binary “solid solvates”, characterized by the distance between the GO planes and the value of sorption. Temperature–composition behavior of the swollen structures was adequately described by conventional binary phase diagrams. Phase transformation of the low-temperature swollen structure of B-GO with 1-nonanol gave a clear example of incongruent melting transition typical for the binary solvates. A discreet set of the interplane distances observed by XRD and the stepwise equilibrium desorption pointed to the layered arrangement of solvent molecules in the swollen structures. The swollen structures with one to five parallel layers were observed for a series of normal alcohols with B-GO. The average volume of one layer, 0.36 ± 0.06 cm3 g–1 B-GO, was almost the same for rather different organic liquids and was possibly restricted by the internal geometry of B-GO. This internal volume available for the sorption of the first layer was reasonably estimated from geometrical parameters of B-GO.

sted, utgiver, år, opplag, sider
American Chemical Society (ACS), 2020
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-177068 (URN)10.1021/acs.jpcc.0c06783 (DOI)000585970300059 ()2-s2.0-85097142196 (Scopus ID)
Forskningsfinansiär
EU, Horizon 2020, 785219EU, Horizon 2020, 881603Swedish Research Council, 2017-04173
Tilgjengelig fra: 2020-12-01 Laget: 2020-12-01 Sist oppdatert: 2022-04-04bibliografisk kontrollert
Iakunkov, A., Sun, J., Rebrikova, A., Korobov, M., Klechikov, A., Vorobiev, A., . . . Talyzin, A. V. (2019). Swelling of graphene oxide membranes in alcohols: effects of molecule size and air ageing. Journal of Materials Chemistry A, 7, 11331-11337
Åpne denne publikasjonen i ny fane eller vindu >>Swelling of graphene oxide membranes in alcohols: effects of molecule size and air ageing
Vise andre…
2019 (engelsk)Inngår i: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 7, s. 11331-11337Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Swelling of Hummers graphene oxide (HGO) membranes in a set of progressively longer liquid alcohols (methanol to 1-nonanol) was studied using synchrotron radiation XRD after air ageing over prolonged periods of time. Both precursor graphite oxides and freshly prepared HGO membranes were found to swell in the whole set of nine liquid alcohols with an increase of interlayer spacing from ∼7 Å (solvent free) up to ∼26 Å (in 1-nonanol). A pronounced effect of ageing on swelling in alcohols was found for HGO membranes stored in air. The HGO membranes aged for 0.5–1.5 years show progressively slower swelling kinetics, a non-monotonic decrease of saturated swelling in some alcohols and complete disappearance of swelling for alcohol molecules larger than hexanol. Moreover, the HGO membranes stored under ambient conditions for 5 years showed a nearly complete absence of swelling in all alcohols but preserved swelling in water. In contrast, precursor graphite oxide powder showed unmodified swelling in alcohols even after 4 years of ageing. Since the swelling defines the size of permeation channels, the ageing effect is one of the important parameters which could explain the strong variation in reported filtration/separation properties of GO membranes. The time and conditions of air storage require standardization for better reproducibility of results related to performance of GO membranes in various applications. The ageing of GO membranes can be considered not only as a hindrance/degradation for certain applications, but also as a method to tune the swelling properties of HGO membranes for better selectivity in sorption of solvents and for achieving better selective permeability.

sted, utgiver, år, opplag, sider
Royal Society of Chemistry, 2019
HSV kategori
Forskningsprogram
fysik
Identifikatorer
urn:nbn:se:umu:diva-160413 (URN)10.1039/C9TA01902B (DOI)000472225200050 ()2-s2.0-85065537331 (Scopus ID)
Forskningsfinansiär
EU, Horizon 2020, 785219The Kempe FoundationsSwedish Research Council, 2017-04173
Tilgjengelig fra: 2019-06-18 Laget: 2019-06-18 Sist oppdatert: 2022-04-04bibliografisk kontrollert
Sun, J., Klechikov, A., Moise, C., Prodana, M., Enachescu, M. & Talyzin, A. (2018). A Molecular Pillar Approach To Grow Vertical Covalent Organic Framework Nanosheets on Graphene: Hybrid Materials for Energy Storage. Angewandte Chemie International Edition, 57(4), 1034-1038
Åpne denne publikasjonen i ny fane eller vindu >>A Molecular Pillar Approach To Grow Vertical Covalent Organic Framework Nanosheets on Graphene: Hybrid Materials for Energy Storage
Vise andre…
2018 (engelsk)Inngår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 57, nr 4, s. 1034-1038Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Hybrid 2D–2D materials composed of perpendicularly oriented covalent organic frameworks (COFs) and graphene were prepared and tested for energy storage applications. Diboronic acid molecules covalently attached to graphene oxide (GO) were used as nucleation sites for directing vertical growth of COF-1 nanosheets (v-COF-GO). The hybrid material has a forest of COF-1 nanosheets with a thickness of 3 to 15 nm in edge-on orientation relative to GO. The reaction performed without molecular pillars resulted in uncontrollable growth of thick COF-1 platelets parallel to the surface of GO. The v-COF-GO was converted into a conductive carbon material preserving the nanostructure of precursor with ultrathin porous carbon nanosheets grafted to graphene in edge-on orientation. It was demonstrated as a high-performance electrode material for supercapacitors. The molecular pillar approach can be used for preparation of many other 2D-2D materials with control of their relative orientation.

sted, utgiver, år, opplag, sider
John Wiley & Sons, 2018
HSV kategori
Forskningsprogram
nanomaterial
Identifikatorer
urn:nbn:se:umu:diva-145739 (URN)10.1002/anie.201710502 (DOI)000428208700030 ()29210484 (PubMedID)2-s2.0-85038626242 (Scopus ID)
Tilgjengelig fra: 2018-03-16 Laget: 2018-03-16 Sist oppdatert: 2023-03-23bibliografisk kontrollert
Sandström, R., Ekspong, J., Annamalai, A., Sharifi, T., Klechikov, A. & Wågberg, T. (2018). Fabrication of microporous layer - free hierarchical gas diffusion electrode as a low Pt-loading PEMFC cathode by direct growth of helical carbon nanofibers. RSC Advances, 8(72), 41566-41574
Åpne denne publikasjonen i ny fane eller vindu >>Fabrication of microporous layer - free hierarchical gas diffusion electrode as a low Pt-loading PEMFC cathode by direct growth of helical carbon nanofibers
Vise andre…
2018 (engelsk)Inngår i: RSC Advances, E-ISSN 2046-2069, Vol. 8, nr 72, s. 41566-41574Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Improving interfacial contact between each component in the proton exchange membrane fuel cell (PEMFC) can lead to a significant increase in power density and Pt utilization. In this work, the junction between the catalyst layer and gas diffusion layer (GDL) is greatly enhanced through direct attachment of helical carbon nanofibers, giving rise to a hierarchical structure within the electrical interconnections. The alternative novel GDL is produced by spraying a thin layer of Pd2C60 precursor on commercial carbon paper, followed by chemical vapor deposition growth resulting in a surface morphology of well-attached nanofibers surrounding the microfibers present in the commercial carbon paper. Subsequent solvothermal deposition of platinum nanoparticles allowed evaluation of its suitability as gas diffusion electrode in cathodic H-2/O-2 PEMFC environment. A combination of lowered charge transfer resistance and enhanced Pt-utilization is attributed to its unique wire-like appearance and its robust properties. The fabricated microporous layer - free GDL is suitable for relatively aggressive membrane electrode assembly fabrication procedures and is produced by industrially favorable techniques, rendering it capable of efficiently supporting small amounts of precious metal catalyst nanoparticles in various PEM applications.

sted, utgiver, år, opplag, sider
Royal Society of Chemistry, 2018
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-155124 (URN)10.1039/c8ra07569g (DOI)000453914300053 ()2-s2.0-85058569317 (Scopus ID)
Forskningsfinansiär
The Kempe FoundationsSwedish Energy AgencySwedish Research Council
Tilgjengelig fra: 2019-01-08 Laget: 2019-01-08 Sist oppdatert: 2023-03-23bibliografisk kontrollert
Klechikov, A., You, S., Lackner, L., Sun, J., Iakunkov, A., Rebrikova, A., . . . Talyzin, A. V. (2018). Graphite oxide swelling in molten sugar alcohols and their aqueous solutions. Carbon, 140, 157-163
Åpne denne publikasjonen i ny fane eller vindu >>Graphite oxide swelling in molten sugar alcohols and their aqueous solutions
Vise andre…
2018 (engelsk)Inngår i: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 140, s. 157-163Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Graphite oxides (GO) are intercalated rapidly by one to several layers of solvent when immersed in liquid but the GO solvates are typically unstable on air due to solvent evaporation. Here we study swelling of GO in solvents (sugar alcohols) with melting temperature point above ambient. Using in situ synchrotron radiation XRD experiments we demonstrated GO swelling in molten xylitol and sorbitol. The expanded GO structure intercalated with one layer of xylitol or sorbitol is preserved upon solidification of melt and cooling back to ambient conditions. The structure of solid solvates of GO with xylitol and sorbitol is based on non-covalent interaction and pristine GO can be recovered by washing in water. Intercalation of xylitol and sorbitol into GO structure in aqueous solutions yields similar but less ordered structure of GO/sugar alcohol solid solvates. Very similar inter-layer distance was observed for GO intercalated by sugar alcohols in melt and for GO immersed in sugar solutions. This result shows that sugar alcohols penetrate into GO inter-layer space without hydration shell forming 2D layers with orientation parallel to graphene oxide sheets. Therefore, hydration diameter of molecules should not be considered as decisive factor for permeation through graphene oxide inter-layers in multilayered membranes.

sted, utgiver, år, opplag, sider
Elsevier, 2018
Emneord
graphene, graphene oxide, swelling
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-151276 (URN)10.1016/j.carbon.2018.08.033 (DOI)000450120200016 ()2-s2.0-85053206382 (Scopus ID)
Forskningsfinansiär
EU, Horizon 2020, 696656Swedish Research CouncilÅForsk (Ångpanneföreningen's Foundation for Research and Development)The Kempe FoundationsEU, Horizon 2020, 785219
Tilgjengelig fra: 2018-08-31 Laget: 2018-08-31 Sist oppdatert: 2022-04-04bibliografisk kontrollert
Klechikov, A. (2018). Graphite oxides for preparation of graphene related materials: structure, chemical modification and hydrogen storage properties. (Doctoral dissertation). Umeå: Umeå University
Åpne denne publikasjonen i ny fane eller vindu >>Graphite oxides for preparation of graphene related materials: structure, chemical modification and hydrogen storage properties
2018 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Carbon materials have been studied for hydrogen storage for decades, but they showed too low capacity at ambient temperature compared to target values for practical applications. This thesis includes two parts. First one is fundamental study of graphite oxides (GO) structure and properties. Second part is focused on hydrogen storage properties of graphene related materials prepared using GO as a precursor.

We studied the effects of synthesis methods and oxidation degree on solvation/intercalation properties of GOs. New effect of temperature induced reversible delamination was observed for Hummers GO (HGO) immersed in liquid acetonitrile. Experiments with swelling of Brodie GO (BGO) in 1-octanol revealed parallel orientation of the intercalated solvent molecules relative to graphene oxide (GnO) layers. Chemical functionalization of GO in swelled state allowed us to synthesize the materials with subnanometer slit pores supported by molecular pillars. Structure and properties of pillared GO were characterized by variety of methods. Swelling properties of multilayered GnO membranes were compared to properties of precursor GO. GnO membranes were found to swell similarly to GO powders in some solvents and rather differently in other. Our experiments revealed important limitations in application of GO membranes for nanofiltration. Several parameters were found to affect the size of permeation “channels” provided by interlayers of GnO membrane structure: e.g. nature of solvent, pH of solutions and concentration of solutes.

Hydrogen storage parameters were studied for a set of graphene related materials with broad range of surface areas (SSA) (200 - 3300 m2/g). Hydrogen sorption weight percent (wt%) is found to correlate with SSA for all studied graphene materials following the trend standard for other nanostructured carbon materials. The highest hydrogen uptakes of ~1.2 wt% at 296 K and ~7.5 wt% at 77 K were measured for graphene material with SSA of over 3000 m2/g. Addition of Pd and Pt nanoparticles to graphene materials did not resulted in improvement of hydrogen storage compared to nanoparticles-free samples. No deviation from the standard wt% vs. SSA trends was also observed for pillared GO materials. Therefore, hydrogen storage properties of graphene related materials at room temperatures are not confirmed to be exceptional. However, high surface area graphene materials are found to be among the best materials for physisorption of hydrogen at liquid nitrogen temperature. Moreover, hydrogen storage capacity of 4 wt%, comparable to target values, was observed at temperature of solid CO2 (193 K) which can be maintained using common refrigeration methods.

sted, utgiver, år, opplag, sider
Umeå: Umeå University, 2018. s. 117
Emneord
Graphite oxide, graphene oxide, hydrogen storage, nanomaterials, adsorption, surface area, pore volume
HSV kategori
Forskningsprogram
materialvetenskap
Identifikatorer
urn:nbn:se:umu:diva-144270 (URN)978-91-7601-841-5 (ISBN)
Disputas
2018-03-02, N430, Naturvetarhuset, Umeå, 13:15 (engelsk)
Opponent
Veileder
Tilgjengelig fra: 2018-02-09 Laget: 2018-01-29 Sist oppdatert: 2018-06-09bibliografisk kontrollert
Iakunkov, A., Klechikov, A., Sun, J., Steenhaut, T., Hermans, S., Filinchuk, Y. & Talyzin, A. V. (2018). Gravimetric tank method to evaluate material-enhanced hydrogen storage by physisorbing materials. Physical Chemistry, Chemical Physics - PCCP, 20(44), 27983-27991
Åpne denne publikasjonen i ny fane eller vindu >>Gravimetric tank method to evaluate material-enhanced hydrogen storage by physisorbing materials
Vise andre…
2018 (engelsk)Inngår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, nr 44, s. 27983-27991Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The most common methods to evaluate hydrogen sorption (volumetric and gravimetric) require significant experience and expensive equipment for providing reproducible results. Both methods allow one to measure excess uptake values which are used to calculate the total amount of hydrogen stored inside of a tank as required for applications. Here we propose an easy to use and inexpensive alternative approach which allows one to evaluate directly the weight of hydrogen inside a material-filled test tank. The weight of the same tank filled with compressed hydrogen in the absence of loaded material is used as a reference. We argue that the only parameter which is of importance for hydrogen storage applications is by how much the material improves the total weight of hydrogen inside of the given volume compared to compressed gas. This parameter which we propose to name Gain includes both volumetric and gravimetric characterization of the material; it can be determined directly without knowing the skeletal volume of the material or excess sorption. The feasibility of the Gravimetric Tank (GT) method was tested using several common carbon and Metal Organic Framework (MOF) materials. The best Gain value of ∼12% was found for the Cu-BTC MOF which means that the tank completely filled with this material stores a 12% higher amount of hydrogen compared to H2 gas at the same PTconditions. The advantages of the GT method are its inexpensive design, extremely simple procedures and direct results in terms of tank capacity as required for industrial applications. The GT method could be proposed as a standard check for verification of the high hydrogen storage capacity of new materials. The GT method is expected to provide even better accuracy for evaluation of a material's performance for storage of denser gases like e.g. CO2 and CH4.

HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-154041 (URN)10.1039/c8cp05241g (DOI)000450660400026 ()30382273 (PubMedID)2-s2.0-85056514432 (Scopus ID)
Forskningsfinansiär
EU, Horizon 2020, 696656EU, Horizon 2020, N785219The Kempe FoundationsSwedish Research Council, 2017-04173
Tilgjengelig fra: 2018-12-19 Laget: 2018-12-19 Sist oppdatert: 2023-03-23bibliografisk kontrollert
Klechikov, A., Sun, J., Vorobiev, A. & Talyzin, A. V. (2018). Swelling of Thin Graphene Oxide Films Studied by in Situ Neutron Reflectivity. The Journal of Physical Chemistry C, 122(24), 13106-13116
Åpne denne publikasjonen i ny fane eller vindu >>Swelling of Thin Graphene Oxide Films Studied by in Situ Neutron Reflectivity
2018 (engelsk)Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, nr 24, s. 13106-13116Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Permeation of multilayered graphene oxide (GO) membranes by polar solvents is known to correlate with their swelling properties and amount of sorbed solvent. However, quantitative estimation of sorption using standard (e.g., gravimetric) methods is technically challenging for few nanometers thick GO membranes/films exposed to solvent vapors. Neutron reflectivity (NR) was used here to evaluate the amount of solvents intercalated into the film which consists of only ∼31.5 layers of GO. Analysis of NR data recorded from the GO film exposed to vapors of polar solvents provides information about change of film thickness due to swelling, amount of intercalated solvent, and selectivity in sorption of solvents from binary mixtures. A quantitative study of GO film sorption was performed for D2O, d-methanol, ethanol, dimethyl sulfoxide (DMSO), acetonitrile, dimethylformamide (DMF), and acetone. Using isotopic contrast, we estimated selectivity in sorption of ethanol/d-methanol mixtures by the GO film. Estimation of sorption selectivity was also performed for D2O/DMF, D2O/DMSO, and D2O/acetonitrile binary mixtures. Sorption of polar solvents was compared for the thin GO film, micrometer thick free standing GO membranes, and graphite oxide powders.

sted, utgiver, år, opplag, sider
American Chemical Society (ACS), 2018
Emneord
graphene, graphene oxide, swelling
HSV kategori
Forskningsprogram
fysik
Identifikatorer
urn:nbn:se:umu:diva-151273 (URN)10.1021/acs.jpcc.8b01616 (DOI)000436381600057 ()2-s2.0-85047617225 (Scopus ID)
Forskningsfinansiär
EU, Horizon 2020
Tilgjengelig fra: 2018-08-31 Laget: 2018-08-31 Sist oppdatert: 2022-04-04bibliografisk kontrollert
Talyzin, A., Mercier, G., Klechikov, A., Hedenström, M., Johnels, D., Wei, D., . . . Moons, E. (2017). Brodie vs Hummers graphite oxides for preparation of multi-layered materials. Carbon, 115, 430-440
Åpne denne publikasjonen i ny fane eller vindu >>Brodie vs Hummers graphite oxides for preparation of multi-layered materials
Vise andre…
2017 (engelsk)Inngår i: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 115, s. 430-440Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Graphite oxides synthesized by one and two step Brodie oxidation (BGO) and Hummers (HGO) methods were analyzed by a variety of characterization methods in order to evaluate the reasons behind the difference in their properties. It is found that the Brodie method results in a higher relative amount of hydroxyl groups and a more homogeneous overall distribution of functional groups over the planar surface of the graphene oxide flakes. The higher number of carbonyl and carboxyl groups in HGO, detected by several methods, including XPS, NMR and FTIR, unavoidably results in defects of the graphene "skeleton", holes and overall disruption of the carbon-carbon bond network, stronger deviation from planar flake shape and poor ordering of the graphene oxide layers. It is also suggested that functional groups in HGO are less homogeneously distributed over the flake surface, forming some nanometer-sized graphene areas. The presence of differently oxidized areas on the GO surface results in inhomogeneous solvation and hydration of HGO and effects of inter- and intra-stratification. The proposed interpretation of the data explains the higher mechanical strength of multi-layered BGO membranes/papers, which are also less affected by humidity changes, thus providing an example of a membrane property superior to that of HGO.

sted, utgiver, år, opplag, sider
Elsevier, 2017
Emneord
graphite, oxide
HSV kategori
Forskningsprogram
fysik
Identifikatorer
urn:nbn:se:umu:diva-130949 (URN)10.1016/j.carbon.2016.12.097 (DOI)000395601300045 ()2-s2.0-85009806799 (Scopus ID)
Tilgjengelig fra: 2017-02-01 Laget: 2017-02-01 Sist oppdatert: 2023-03-24bibliografisk kontrollert
Klechikov, A., Sun, J., Hu, G., Zheng, M., Wågberg, T. & Talyzin, A. V. (2017). Graphene decorated with metal nanoparticles: Hydrogen sorption and related artefacts. Microporous and Mesoporous Materials, 250, 27-34
Åpne denne publikasjonen i ny fane eller vindu >>Graphene decorated with metal nanoparticles: Hydrogen sorption and related artefacts
Vise andre…
2017 (engelsk)Inngår i: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 250, s. 27-34Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Hydrogen sorption by reduced graphene oxides (r-GO) is not found to increase after decoration with Pd and Pt nanoparticles. Treatments of metal decorated samples using annealing under hydrogen or air were tested as a method to create additional pores by effects of r-GO etching around nanoparticles. Increase of Specific Surface Area (SSA) was observed for some air annealed r-GO samples. However, the same treatments applied to activated r-GO samples with microporous nature and higher surface area result in breakup of structure and dramatic decrease of SSA. Our experiments have not revealed effects which could be attributed to spillover in hydrogen sorption on Pd or Pt decorated graphene. However, we report irreversible chemisorption of hydrogen for some samples which can be mistakenly assigned to spillover if the experiments are incomplete.

Emneord
Graphene, Hydrogen storage, Graphene oxide, Nanoparticles, Decoration
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-135589 (URN)10.1016/j.micromeso.2017.05.014 (DOI)000405045800004 ()2-s2.0-85018860922 (Scopus ID)
Forskningsfinansiär
EU, Horizon 2020
Tilgjengelig fra: 2017-05-31 Laget: 2017-05-31 Sist oppdatert: 2023-03-24bibliografisk kontrollert
Organisasjoner