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Martinez U, Dumont JH, Holby EF, Artyushkova K, Purdy GM, Singh A, Mack NH, Atanassov P, Cullen DA, More KL, Chhowalla M, Zelenay P, Dattelbaum AM, Mohite AD, Gupta G. Critical role of intercalated water for electrocatalytically active nitrogen-doped graphitic systems. SCIENCE ADVANCES 2016; 2:e1501178. [PMID: 27034981 PMCID: PMC4803488 DOI: 10.1126/sciadv.1501178] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 01/14/2016] [Indexed: 05/30/2023]
Abstract
Graphitic materials are essential in energy conversion and storage because of their excellent chemical and electrical properties. The strategy for obtaining functional graphitic materials involves graphite oxidation and subsequent dissolution in aqueous media, forming graphene-oxide nanosheets (GNs). Restacked GNs contain substantial intercalated water that can react with heteroatom dopants or the graphene lattice during reduction. We demonstrate that removal of intercalated water using simple solvent treatments causes significant structural reorganization, substantially affecting the oxygen reduction reaction (ORR) activity and stability of nitrogen-doped graphitic systems. Amid contrasting reports describing the ORR activity of GN-based catalysts in alkaline electrolytes, we demonstrate superior activity in an acidic electrolyte with an onset potential of ~0.9 V, a half-wave potential (E ½) of 0.71 V, and a selectivity for four-electron reduction of >95%. Further, durability testing showed E ½ retention >95% in N2- and O2-saturated solutions after 2000 cycles, demonstrating the highest ORR activity and stability reported to date for GN-based electrocatalysts in acidic media.
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Affiliation(s)
- Ulises Martinez
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Joseph H. Dumont
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
- Department of Chemical and Biological Engineering, University of New Mexico, Albuquerque, NM 87131, USA
| | - Edward F. Holby
- Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Kateryna Artyushkova
- Department of Chemical and Biological Engineering, University of New Mexico, Albuquerque, NM 87131, USA
| | - Geraldine M. Purdy
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Akhilesh Singh
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Nathan H. Mack
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Plamen Atanassov
- Department of Chemical and Biological Engineering, University of New Mexico, Albuquerque, NM 87131, USA
| | - David A. Cullen
- Materials Science and Technology Division, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Karren L. More
- Materials Science and Technology Division, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Manish Chhowalla
- Science and Engineering, Rutgers University, 607 Taylor Road, Piscataway, NJ 08854, USA
| | - Piotr Zelenay
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Andrew M. Dattelbaum
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Aditya D. Mohite
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Gautam Gupta
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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Pathak H, Wölk J, Strey R, Wyslouzil BE. Co-condensation of nonane and D2O in a supersonic nozzle. J Chem Phys 2014; 140:034304. [DOI: 10.1063/1.4861052] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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Bhabhe A, Pathak H, Wyslouzil BE. Freezing of Heavy Water (D2O) Nanodroplets. J Phys Chem A 2013; 117:5472-82. [DOI: 10.1021/jp400070v] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Ashutosh Bhabhe
- William G.
Lowrie Department
of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio 43210, United States
| | - Harshad Pathak
- William G.
Lowrie Department
of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio 43210, United States
| | - Barbara E. Wyslouzil
- William G.
Lowrie Department
of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio 43210, United States
- Department of Chemistry and
Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
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Hujo W, Gaus M, Schultze M, Kubař T, Grunenberg J, Elstner M, Bauerecker S. Effect of Nitrogen Adsorption on the Mid-Infrared Spectrum of Water Clusters. J Phys Chem A 2011; 115:6218-25. [DOI: 10.1021/jp111481q] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Waldemar Hujo
- Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, Hans-Sommer-Strasse 10, D-38106 Braunschweig, Germany
| | - Michael Gaus
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Markus Schultze
- Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, Hans-Sommer-Strasse 10, D-38106 Braunschweig, Germany
| | - Tomáš Kubař
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Jörg Grunenberg
- Institut für Organische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Marcus Elstner
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Sigurd Bauerecker
- Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, Hans-Sommer-Strasse 10, D-38106 Braunschweig, Germany
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Monreal IA, Devlin JP, Maşlakcı Z, Çiçek MB, Uras-Aytemiz N. Controlling Nonclassical Content of Clathrate Hydrates Through the Choice of Molecular Guests and Temperature. J Phys Chem A 2010; 115:5822-32. [DOI: 10.1021/jp109620b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- I. Abrrey Monreal
- Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - J. Paul Devlin
- Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Zafer Maşlakcı
- Department of Chemistry, Suleyman Demirel University, 32260 Isparta, Turkey
| | - M. Bora Çiçek
- Department of Chemistry, Suleyman Demirel University, 32260 Isparta, Turkey
| | - Nevin Uras-Aytemiz
- Department of Chemistry, Suleyman Demirel University, 32260 Isparta, Turkey
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Gulluru DB, Devlin JP. Rates and Mechanisms of Conversion of Ice Nanocrystals to Ether Clathrate Hydrates: Guest-Molecule Catalytic Effects at ∼120 K. J Phys Chem A 2006; 110:1901-6. [PMID: 16451023 DOI: 10.1021/jp056254u] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A Fourier transform infrared investigation of the rates and energetics of conversion of ice nanocrystals within 3-D arrays to ether clathrate-hydrate (CH) particles at approximately 120 K is reported. After an induction period, apparently necessitated by relatively slow nucleation of the CH phase, the well-established shrinking-core model of particle-adsorbate reaction applies to these conversions in the presence of an abundance of adsorbed ether. This implies that the transport of the ether adsorbate through the product crust encasing a reacting particle core (a necessary aspect of a particle reaction mechanism) is the rate-controlling factor. Diffusion moves adsorbed reactant molecules to the reaction zone at the interface of the ice core with the product (CH) crust. The results indicate that ether hydrate formation rates near 120 K resemble rates for gas hydrates measured near 260 K, implying rates greater by many orders of magnitude for comparable temperatures. A surprising secondary enhancement of ether CH-formation rates by the simultaneous incorporation of simple small gas molecules (N2, CO2, CH4, CO, and N2O) has also been quantified in this study. The rapid CH formation at low temperatures is conjectured to derive from defect-facilitated transport of reactants to an interfacial reaction zone, with the defect populations enhanced through transient H bonding of guest-ether proton-acceptor groups with O-H groups of the hydrate cage walls.
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Affiliation(s)
- Dheeraj B Gulluru
- Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, USA
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Devlin JP, Gulluru DB, Buch V. Rates and Mechanisms of Conversion of Ice Nanocrystals to Hydrates of HCl and HBr: Acid Diffusion in the Ionic Hydrates. J Phys Chem B 2005; 109:3392-401. [PMID: 16851370 DOI: 10.1021/jp0456281] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
This FTIR study focuses on solid-state chemistry associated with formation and interconversion of the ionic HX (X = Cl, Br) hydrates. Kinetic data are reported for conversions of ice nanocrystal arrays exposed to the saturation pressure of the acids in the 110 approximately 125 K range. The product is amorphous acid dihydrate in the case of HBr, and amorphous monohydrate for HCl. The rate-determining step is identified as HX diffusion through the hydrate product crust toward the interfacial reaction zone, rather than diffusion through ice, as commonly believed. Slowing of the conversion process is thus observed with increasing thickness of the crust. The diffusion coefficient (D(e)) and activation energy values for HX diffusion through the hydrates were evaluated with the help of the shrinking-core model. Hydrate crystallization occurs as a separate step, upon heating above 130 K. Subsequently, rates of reversible transitions between crystal di- and monohydrates were observed upon exposure to acid vapor and acid evacuation. In conversion from di- to monohydrate, the rate slows after fast formation of several layers; subsequently, diffusion through the product crust appears to be the rate-controlling step. The activation energy for HBr diffusion through crystal dihydrate is found to be significantly higher than that for the amorphous analogue. Conjecture is offered for a molecular mechanism of HX transport through the crystal hydrate, based on (i) spectroscopic/computational evidence for the presence of molecular HX bonded to X(-) in each of the ionic hydrate phases and (ii) the relative E(a) values found for HBr and HCl diffusion. Monte Carlo modeling suggests acid transport to the reaction zone along boundaries between "nanocrystallites" generated by multiple hydrate nucleation events at the particle surfaces. The reverse conversion, of crystalline monohydrate particles to the dihydrate phase, as well as dihydrate to trihydrate, displays nearly constant rate throughout the particle conversion; suggesting desorption of HX from the particle surface as the rate-limiting factor. Like for D(e), the activation energies for desorption were found to be approximately 20% greater for HCl than HBr for related hydrate phases.
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Affiliation(s)
- J Paul Devlin
- Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
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Devlin JP, Farník M, Suhm MA, Buch V. Comparative FTIR Spectroscopy of HX Adsorbed on Solid Water: Ragout-Jet Water Clusters vs Ice Nanocrystal Arrays. J Phys Chem A 2005; 109:955-8. [PMID: 16833399 DOI: 10.1021/jp044212k] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In addition to revealing the stretch-mode bands of the smallest mixed clusters of HCl and HBr (HX) with water, the ragout-jet FTIR spectra of dense mixed water-acid supersonic jets include bands that result from the interaction of HX with larger water clusters. It is argued here that low jet temperatures prevent the water-cluster-bound HX molecules from becoming sufficiently solvated to induce ionic dissociation. The molecular nature of the HX can be deduced directly from the observed influence of changing from HCl to HBr and from replacing H2O with D2O. Furthermore, the band positions of HX are roughly coincidental with bands assigned to molecular HCl and HBr adsorbed on ice nanocrystal surfaces at temperatures below 100 K. It is also interesting that the HX band positions and widths approximate those of HX bound to the surface of amorphous ice films at <60 K. Though computational results suggest the adsorbed HX molecules observed in the jet expansions are weakly distorted by single coordination with surface dangling-oxygen atoms, on-the-fly trajectories indicate that the cluster skeletons undergo large-amplitude low-frequency vibrations. Local HX solvation, the extent of proton sharing, and the HX vibrational spectra undergo serious modulation on a picosecond time scale.
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Steinbach C, Andersson P, Kazimirski JK, Buck U, Buch V, Beu TA. Infrared Predissociation Spectroscopy of Large Water Clusters: A Unique Probe of Cluster Surfaces. J Phys Chem A 2004. [DOI: 10.1021/jp049276+] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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