The utilization of zinc recovered from alkaline battery waste as metal precursor in the synthesis of metal-organic framework

Vellingiri, Kowsalya,Tsang, Daniel C.W.,Kim, Ki-Hyun,Deep, Akash,Dutta, Tanushree,Boukhvalov, Danil W. Elsevier 2018 Journal of Cleaner Production Vol.199 No.-

<P><B>Abstract</B></P> <P>In the treatment of spent wastes, seeking extra economic incentives (e.g., through their regeneration into value-added end products) along with environmental protection is a highly ideal option to consider. In this context, a process was developed to utilize spent alkaline battery waste as a source medium of zinc (Zn<SUP>2+</SUP>) ions for the synthesis of a high-value material, metal organic frameworks (MOFs). For this purpose, multiple options including acid leaching and base precipitation were first compared for separation of Zn<SUP>2+</SUP> ions from battery waste. Secondly, MOF-5 synthesis was carried out through two different routes: one using the Zn<SUP>2+</SUP> ions separated from waste batteries (W-MOF-5) and the other using pure chemicals (P-MOF-5). Finally, differences in the structural properties (e.g., crystallinity and morphology) between the two MOF-5 types were assessed through characterization experiments (e.g., FTIR, PXRD, and SEM analyses) and modeling (DFT) studies. W-MOF-5 was found to possess tetragonal lattice parameters which indicated decrease in the Zn<SUP>2+</SUP> ions in the framework. This deficiency increased the interplanar Bragg angles which led to the different size and shape of W-MOF-5. Also, the PXRD spectrum indicated the presence of all peaks at similar position with that of P-MOF-5. Additionally, the preparation of 1 kg of W-MOF-5 requires a low cost (42 USD) when one considers >90% of solvent recovery. Also in terms of materials cost, the synthesis of W-MOF-5 was highly cost-effective than that of ZnO nanoparticles. In light of many compatibilities between MOFs synthesized through the two different routes, the method proposed in this work can be further developed toward a simple, fast, and reliable route for MOF-5 production from battery waste.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Engineering ferromagnetic lines in graphene by local functionalization using AFM lithography

Bae Ho Park,Ik-Su Byun,Danil W. Boukhvalov,Duk Hyun Lee,Wondong Kim,Jaeyoon Baik,Hyun-Joon Shin,Young-Woo Son 한국자기학회 2021 한국자기학회 학술연구발표회 논문개요집 Vol.31 No.1

Monolayer graphene with sp²-carbon-atom network is a promising platform for next-generation spintronic devices due to its high carrier mobility and long spin relaxation length. For implementation of practical and high-density graphene-based spintronic devices, we need to define nanoscale areas with ferromagnetic properties on graphene. Up to now, conventional ferromagnetic metal electrodes accompanied by barrier insulators have been used for injection and detection of polarized spins in graphene-based spintronic devices. If graphene-based materials show ferromagnetic behaviors, they will become ideal candidates for spin injectors and detectors, because they structurally, chemically, and electrically match well with pristine graphene. In this presentation, I will report on local magnetic characteristics of nanoscale graphene oxidized and hydrogenated by atomic force microscope (AFM) lithography without conventional sources of surface contamination and chemical agents. By using AFM lithography, we can selectively control functional groups and their coverages on the nanoscale at the surface of graphene. By performing magnetic force microscope (MFM) measurement, we can clearly distinguish local magnetic signal of selectively oxidized or hydrogenated graphene from that of surrounding pristine graphene which does not produce ferromagnetic signal. The nanoscale oxidized and hydrogenated graphene show experimental evidences for room-temperature ferromagnetism. From x-ray magnetic circular dichroism photoemission electron microscope (XMCD-PEEM) measurement, we also identified remarkable asymmetry in carbon K edge XMCD spectra, which strongly indicates that the observed ferromagnetic order in functionalized graphene layers is intrinsic.

sp-Electron Magnetic Clusters with a Large Spin in Graphene

Boukhvalov, Danil W.,Katsnelson, Mikhail I. American Chemical Society 2011 ACS NANO Vol.5 No.4

<P>Motivated by recent experimental data (Sepioni, M.; <I>et al. Phys. Rev. Lett</I>. <B>2010</B>, <I>105</I>, 207−205), we have studied the possibility of forming magnetic clusters with spin <I>S</I> > <SUP>1</SUP>/<SUB>2</SUB> on graphene by adsorption of hydrogen atoms or hydroxyl groups. Migration of hydrogen atoms and hydroxyl groups on the surface of graphene during the delamination of HOPG led to the formation of seven atom or seven OH-group clusters with <I>S</I> = <SUP>5</SUP>/<SUB>2</SUB> that were of a special interest. The coincidence of symmetry of the clusters with the graphene lattice strengthens the stability of the cluster. For (OH)<SUB>7</SUB> clusters that were situated greater than 3 nm from one another, the reconstruction barrier to a nonmagnetic configuration was approximately 0.4 eV, whereas for H<SUB>7</SUB> clusters, there was no barrier and the high-spin state was unstable. Stability of the high-spin clusters increased if they were formed on top of ripples. Exchange interactions between the clusters were studied and we have shown that the ferromagnetic state is improbable. The role of the chemical composition of the solvent used for the delamination of graphite is discussed.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2011/ancac3.2011.5.issue-4/nn103510c/production/images/medium/nn-2010-03510c_0001.gif'></P>

Oxygen reduction reactions on pure and nitrogen-doped graphene: a first-principles modeling

Boukhvalov, Danil W.,Son, Young-Woo The Royal Society of Chemistry 2012 Nanoscale Vol.4 No.2

<P>Based on first principles density functional theory calculations we explored energetics of oxygen reduction reaction over pristine and nitrogen-doped graphene with different amounts of nitrogen doping. The process of oxygen reduction requires one more step than the same reaction catalyzed by metals. Results of calculations evidence that for the case of light doped graphene (about 4% of nitrogen) the energy barrier for each step is lower than for the same process on a Pt surface. In contrast to the catalysis on a metal surface the maximal coverage of doped graphene is lower and depends on the corrugation of graphene. Changes of the energy barriers caused by oxygen load and corrugation are also discussed.</P>

Origin of Anomalous Water Permeation through Graphene Oxide Membrane

Boukhvalov, Danil W.,Katsnelson, Mikhail I.,Son, Young-Woo American Chemical Society 2013 Nano letters Vol.13 No.8

<P>Water inside the low-dimensional carbon structures has been considered seriously owing to fundamental interest in its flow and structures as well as its practical impact. Recently, the anomalous perfect penetration of water through graphene oxide membrane was demonstrated although the membrane was impenetrable for other liquids and even gases. The unusual auxetic behavior of graphene oxide in the presence of water was also reported. Here, on the basis of first-principles calculations, we establish atomistic models for hybrid systems composed of water and graphene oxides revealing the anomalous water behavior inside the stacked graphene oxides. We show that formation of hexagonal ice bilayer in between the flakes as well as melting transition of ice at the edges of flakes are crucial to realize the perfect water permeation across the whole stacked structures. The distance between adjacent layers that can be controlled either by oxygen reduction process or pressure is shown to determine the water flow thus highlighting a unique water dynamics in randomly connected two-dimensional spaces.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2013/nalefd.2013.13.issue-8/nl4020292/production/images/medium/nl-2013-020292_0005.gif'></P>

A Computational Investigation of the Catalytic Properties of Graphene Oxide: Exploring Mechanisms by using DFT Methods

Boukhvalov, Danil W.,Dreyer, Daniel R.,Bielawski, Christopher W.,Son, Young‐,Woo Wiley (John WileySons) 2012 ChemCatChem Vol.4 No.11

Luminescent metal-organic frameworks for the detection of nitrobenzene in aqueous media

Vellingiri, Kowsalya,Boukhvalov, Danil W.,Pandey, Sudhir Kumar,Deep, Akash,Kim, Ki-Hyun Elsevier 2017 Sensors and actuators. B Chemical Vol.245 No.-

<P><B>Abstract</B></P> <P>The feasibility of highly water stable Zr-based metal organic frameworks (MOFs: UiO-66-NH<SUB>2</SUB>) as a sensing probe material was explored for the detection of the electron deficient nitrobenzene (NB) molecule in an aqueous phase. The probe system was highly sensitive toward the NB molecule within the range of 10–100ppm with a linear range of 0–30ppm and a quenching efficiency of around 95% (at 100ppm). The limit of detection (LOD) of the proposed probe was estimated to be 0.9ppm. In contrast, this method was not affected sensitively by potential interferences such as other aromatic compounds. For instance, benzene (B), toluene (T), and chlorobenzene (CB) showed reduced quenching efficiencies (<40%). The specificity toward NB molecules for the proposed probe was appreciable in the presence of co-existing components (B, T, and CB). DFT calculations showed that the sensing mechanism was ascribable to electron transfer from the excited missed-linker induced sites of the ZrOH to the NB molecule. This interaction was confirmed by an FTIR analysis of the UiO-66-NH<SUB>2</SUB>-NB material. Therefore, the proposed UiO-66-NH<SUB>2</SUB> probe can be used as a potent sensing material for the NB even at low concentrations in an aqueous medium.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Quenching mechanism of the metal-organic frameworks (MOFs) is good for sensing hazardous compounds. </LI> <LI> The environmental significance of nitro aromatic compounds is well known due to their health impacts. </LI> <LI> The sensing efficiency of a Zr-based MOFs (UiO-66-NH<SUB>2</SUB>) is assessed against the detection of nitrobenzene. </LI> <LI> The performance of UiO-66-NH<SUB>2</SUB> was demonstrated along with the temporal stability and regenerability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Computational calculation identified optimal binding sites in nano-sized magnetic-cored dendrimer

Kim, Hye-Ran,Boukhvalov, Danil W.,Lee, Soo-Jin,Park, Jae-Woo Elsevier 2018 CHEMOSPHERE - Vol.210 No.-

<P><B>Abstract</B></P> <P>Magnetic-cored dendrimers (MDs) with amino groups were prepared with the formation of poly(amidoamine) dendrimer on the surface of magnetite nanoparticles (MNPs). The experiment involved the binding of four different heavy metal ions including Pb (II), Cu (II), Zn (II), and Cr (VI). Density functional theory (DFT) calculation was applied to the experimental results to determine the optimal configurations between the heavy metal species and generation 1 amino (NH<SUB>2</SUB>) functionalized MD (G1-NH<SUB>2</SUB>-MD). Different binding configurations among the possible binding positions of inner and outer G1-NH<SUB>2</SUB>-MD were determined with the ionic radius and coordination number of each heavy metal ion. Although Pb<SUP>2+</SUP> and Zn<SUP>2+</SUP> were stable in the terminal positions, Cu<SUP>2+</SUP> was the most stable in the internal position. The oxygen and hydrogen atoms of HCrO<SUB>4</SUB> <SUP>−</SUP> formed a hydrogen bond with the NH<SUB>2</SUB> groups, and thus dipole-nonpolar molecular interaction occurred with the CH<SUB>2</SUB> groups of G1-NH<SUB>2</SUB>-MD. Specific binding positions and energies of different heavy metal species were identified through the DFT calculation in the study. The DFT calculation results also contributed to an understanding of the binding priority of each metal ions in the mixed solution. Furthermore, Pb<SUP>2+</SUP> was preferably adsorbed in the mixed solution of Pb<SUP>2+</SUP>, Cu<SUP>2+</SUP>, and Zn<SUP>2+</SUP>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Binding of four metal ions to magnetic-cored dendrimer was examined. </LI> <LI> Binding configuration and energies were calculated using density functional theory. </LI> <LI> Stable configuration between each ion and the dendrimer was identified. </LI> <LI> Pb<SUP>2+</SUP> was preferably adsorbed in the mixed solution of Pb<SUP>2+</SUP>, Cu<SUP>2+</SUP>, and Zn<SUP>2+</SUP>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Hydrogen Dissociation Catalyzed by Carbon‐Coated Nickel Nanoparticles: Experiment and Theory

Yermakov, Anatoliy Ye.,Boukhvalov, Danil W.,Uimin, Michael A.,Lokteva, Ekaterina S.,Erokhin, Alexey V.,Schegoleva, Nina N. WILEY‐VCH Verlag 2013 Chemphyschem Vol.14 No.2

<P><B>Abstract</B></P><P>Based on the combination of experimental measurements and first‐principles calculations we report a novel carbon‐based catalytic material and describe significant acceleration of the hydrogenation of magnesium at room temperature in the presence of nickel nanoparticles wrapped in multilayer graphene. The increase in rate of magnesium hydrogenation in contrast to a mix of graphite and nickel nanoparticles evidences intrinsic catalytic properties of the nanocomposites explored. The results from simulation demonstrate that doping of the metal substrate and the presence of Stone–Wales defects turn multilayer graphene from being chemically inert to chemically active. The role of the size of the nanoparticles and temperature are also discussed.</P>

Electrical control of nanoscale functionalization in graphene by the scanning probe technique

Byun, Ik-Su,Kim, Wondong,Boukhvalov, Danil W.,Hwang, Inrok,Son, Jong Wan,Oh, Gwangtaek,Choi, Jin Sik,Yoon, Duhee,Cheong, Hyeonsik,Baik, Jaeyoon,Shin, Hyun-Joon,Shiu, Hung Wei,Chen, Chia-Hao,Son, Young Nature Publishing Group (NPG) ; Tokyo Institute of 2014 NPG Asia Materials Vol.6 No.-

Functionalized graphene is a versatile material that has well-known physical and chemical properties depending on functional groups and their coverage. However, selective control of functional groups on the nanoscale is hardly achievable by conventional methods utilizing chemical modifications. We demonstrate electrical control of nanoscale functionalization of graphene with the desired chemical coverage of a selective functional group by atomic force microscopy (AFM) lithography and their full recovery through moderate thermal treatments. Surprisingly, our controlled coverage of functional groups can reach 94.9% for oxygen and 49.0% for hydrogen, respectively, well beyond those achieved by conventional methods. This coverage is almost at the theoretical maximum, which is verified through scanning photoelectron microscope measurements as well as first-principles calculations. We believe that the present method is now ready to realize 'chemical pencil drawing' of atomically defined circuit devices on top of a monolayer of graphene.