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White JL, Rowberg AJE, Wan LF, Kang S, Ogitsu T, Kolasinski RD, Whaley JA, Baker AA, Lee JRI, Liu YS, Trotochaud L, Guo J, Stavila V, Prendergast D, Bluhm H, Allendorf MD, Wood BC, El Gabaly F. Identifying the Role of Dynamic Surface Hydroxides in the Dehydrogenation of Ti-Doped NaAlH 4. ACS APPLIED MATERIALS & INTERFACES 2019; 11:4930-4941. [PMID: 30630309 DOI: 10.1021/acsami.8b17650] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Solid-state metal hydrides are prime candidates to replace compressed hydrogen for fuel cell vehicles due to their high volumetric capacities. Sodium aluminum hydride has long been studied as an archetype for higher-capacity metal hydrides, with improved reversibility demonstrated through the addition of titanium catalysts; however, atomistic mechanisms for surface processes, including hydrogen desorption, are still uncertain. Here, operando and ex situ measurements from a suite of diagnostic tools probing multiple length scales are combined with ab initio simulations to provide a detailed and unbiased view of the evolution of the surface chemistry during hydrogen release. In contrast to some previously proposed mechanisms, the titanium dopant does not directly facilitate desorption at the surface. Instead, oxidized surface species, even on well-protected NaAlH4 samples, evolve during dehydrogenation to form surface hydroxides with differing levels of hydrogen saturation. Additionally, the presence of these oxidized species leads to considerably lower computed barriers for H2 formation compared to pristine hydride surfaces, suggesting that oxygen may actively participate in hydrogen release, rather than merely inhibiting diffusion as is commonly presumed. These results demonstrate how close experiment-theory feedback can elucidate mechanistic understanding of complex metal hydride chemistry and potentially impactful roles of unavoidable surface impurities.
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Affiliation(s)
- James L White
- Sandia National Laboratories , Livermore , California 94550 , United States
| | - Andrew J E Rowberg
- Lawrence Livermore National Laboratory , Livermore , California 94550 , United States
- University of California Santa Barbara , Santa Barbara , California 93106 , United States
| | - Liwen F Wan
- Lawrence Livermore National Laboratory , Livermore , California 94550 , United States
- Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - ShinYoung Kang
- Lawrence Livermore National Laboratory , Livermore , California 94550 , United States
| | - Tadashi Ogitsu
- Lawrence Livermore National Laboratory , Livermore , California 94550 , United States
| | | | - Josh A Whaley
- Sandia National Laboratories , Livermore , California 94550 , United States
| | - Alexander A Baker
- Lawrence Livermore National Laboratory , Livermore , California 94550 , United States
| | - Jonathan R I Lee
- Lawrence Livermore National Laboratory , Livermore , California 94550 , United States
| | - Yi-Sheng Liu
- Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Lena Trotochaud
- Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Jinghua Guo
- Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Vitalie Stavila
- Sandia National Laboratories , Livermore , California 94550 , United States
| | - David Prendergast
- Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Hendrik Bluhm
- Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Mark D Allendorf
- Sandia National Laboratories , Livermore , California 94550 , United States
| | - Brandon C Wood
- Lawrence Livermore National Laboratory , Livermore , California 94550 , United States
| | - Farid El Gabaly
- Sandia National Laboratories , Livermore , California 94550 , United States
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Samolia M, Kumar TJD. A conceptual DFT study of the hydrogen trapping efficiency in metal functionalized BN system. RSC Adv 2014. [DOI: 10.1039/c4ra03707c] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We investigate the hydrogen trapping efficiency of various metals functionalized on BN systems for potential hydrogen storage applications using conceptual DFT’s stability and reactivity descriptors.
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Affiliation(s)
- Madhu Samolia
- Department of Chemistry
- Indian Institute of Technology Ropar
- Rupnagar 140001, India
| | - T. J. Dhilip Kumar
- Department of Chemistry
- Indian Institute of Technology Ropar
- Rupnagar 140001, India
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3
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Knight DA, Teprovich JA, Summers A, Peters B, Ward PA, Compton RN, Zidan R. Synthesis, characterization, and reversible hydrogen sorption study of sodium-doped fullerene. NANOTECHNOLOGY 2013; 24:455601. [PMID: 24129505 DOI: 10.1088/0957-4484/24/45/455601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Herein is presented a novel, straightforward route to the synthesis of an alkali metal-doped fullerene as well as a detailed account of its reversible and enhanced hydrogen sorption properties in comparison to pure C60. This work demonstrates that a reaction of sodium hydride with fullerene (C60) results in the formation of a sodium-doped fullerene capable of reversible hydrogen sorption via a chemisorption mechanism. This material not only demonstrated reversible hydrogen storage over several cycles, it also showed the ability to reabsorb over three times the amount of hydrogen (relative to the hydrogen content of NaH) under optimized conditions. The sodium-doped fullerene was hydrogenated on a pressure composition temperature (PCT) instrument at 275 °C while under 100 bar of hydrogen pressure. The hydrogen desorption behavior of this sodium-doped fullerene hydride was observed over a temperature range up to 375 °C on the PCT and up to 550 °C on the thermogravimetric analysis (TGA). Powder x-ray diffraction verifies the identity of this material as being Na6C60. Characterization of this material by thermal decomposition analysis (e.g. PCT and TGA methods), as well as FT-IR and mass spectrometry, indicates that the hydrogen sorption activity of this material is due to the reversible formation of a hydrogenated fullerene (fullerane). However, the reversible formation of fullerane was found to be greatly enhanced by the presence of sodium. It was also demonstrated that the addition of a catalytic amount of titanium (via TiO2 or Ti(OBu)4) further enhances the hydrogen sorption process of the sodium-doped fullerene material.
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Affiliation(s)
- Douglas A Knight
- Savannah River National Laboratory, Clean Energy Directorate, 301 Gateways Dr., Aiken, SC 29808, USA
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PUKAZHSELVAN D, SINHA ASK, SRIVASTAVA ON. STUDIES ON TiO2 NANOPARTICLES AS CATALYST FOR ENHANCED DESORPTION CHARACTERISTICS OF NaAlH4. INTERNATIONAL JOURNAL OF NANOSCIENCE 2012. [DOI: 10.1142/s0219581x11009015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
TiO 2 (np) has been found to be an effective catalyst over ZrO 2 (np) for improving the hydrogen storage characteristics of NaAlH 4. TiO 2 catalyst reduces the activation energy of NaAlH 4 to a better extent than ZrO 2. In the reversibly hydrogenated materials, a substantial reduction in the dehydrogenation temperature could be achieved using TiO 2 catalyst. Such effect was not observed through ZrO 2. The activation energy of the reversibly hydrogenated NaAlH 4 catalyzed by TiO 2 nanoparticles obtained in the present study (60 kJ/mol H2 ) is smaller than that of TiO 2: NaAlH 4 starting material (101.9 kJ/mol H2 ). The stability of the intermediate phase Na 3 AlH 6 in the presence of TiO 2 catalyst was studied through TPD and TPA analysis. XRD analysis confirms that only TiO 2 gets reduced during dehydrogenation; therefore, the observed effect is attributed to the consequence of reduction of TiO 2.
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Affiliation(s)
- D. PUKAZHSELVAN
- Unit of Nano Science and Technology, Physics Department, Banaras Hindu University, Varanasi UP, India
| | - A. S. K. SINHA
- Department of Chemical Engineering Institute of Technology, Banaras Hindu University, Varanasi UP, India
| | - O. N. SRIVASTAVA
- Unit of Nano Science and Technology, Physics Department, Banaras Hindu University, Varanasi UP, India
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Chen JC, Ramos M, Arasa C, Juanes-Marcos JC, Somers MF, Martínez AE, Díaz C, Olsen RA, Kroes GJ. Dynamics of H2 dissociation on the 1/2 ML c(2 × 2)-Ti/Al(100) surface. Phys Chem Chem Phys 2012; 14:3234-47. [PMID: 22294155 DOI: 10.1039/c2cp23693a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dissociation of H(2) on Ti-covered Al surfaces is relevant to the rehydrogenation and dehydrogenation of the NaAlH(4) hydrogen storage material. The energetically most stable structure for a 1/2 monolayer of Ti deposited on the Al(100) surface has the Ti atoms in the second layer with a c(2 × 2) structure, as has been confirmed by both low-energy electron diffraction and low-energy ion scattering experiments and density functional theory studies. In this work, we investigate the dynamics of H(2) dissociation on a slab model of this Ti/Al(100) surface. Two six-dimensional potential energy surfaces (PESs) have been built for this H(2) + Ti/Al(100) system, based on the density functional theory PW91 and RPBE exchange-correlation functionals. In the PW91 (RPBE) PES, the lowest H(2) dissociation barrier is found to be 0.65 (0.84) eV, with the minimum energy path occurring for H(2) dissociating above the bridge to top sites. Using both PESs, H(2) dissociation probabilities are calculated using the classical trajectory (CT), the quasi-classical trajectory (QCT), and the time-dependent wave-packet methods. We find that the QCT H(2) dissociation probabilities are in good agreement with the quantum dynamics results in the collision energy range studied up to 1.0 eV. We have also performed molecular beam simulations and present predictions for molecular beam experiments. Our molecular beam simulations show that H(2) dissociation on the 1/2 ML Ti/Al(100) surface is an activated process, and the reaction probability is found to be 6.9% for the PW91 functional and 1.8% for the RPBE at a nozzle temperature of 1700 K. Finally, we have also calculated H(2) dissociation rate constants by applying transition state theory and the QCT method, which could be relevant to modeling Ti-catalyzed rehydrogenation and dehydrogenation of NaAlH(4).
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Affiliation(s)
- Jian-Cheng Chen
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
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Churchard AJ, Banach E, Borgschulte A, Caputo R, Chen JC, Clary D, Fijalkowski KJ, Geerlings H, Genova RV, Grochala W, Jaroń T, Juanes-Marcos JC, Kasemo B, Kroes GJ, Ljubić I, Naujoks N, Nørskov JK, Olsen RA, Pendolino F, Remhof A, Románszki L, Tekin A, Vegge T, Zäch M, Züttel A. A multifaceted approach to hydrogen storage. Phys Chem Chem Phys 2011; 13:16955-72. [PMID: 21887432 DOI: 10.1039/c1cp22312g] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The widespread adoption of hydrogen as an energy carrier could bring significant benefits, but only if a number of currently intractable problems can be overcome. Not the least of these is the problem of storage, particularly when aimed at use onboard light-vehicles. The aim of this overview is to look in depth at a number of areas linked by the recently concluded HYDROGEN research network, representing an intentionally multi-faceted selection with the goal of advancing the field on a number of fronts simultaneously. For the general reader we provide a concise outline of the main approaches to storing hydrogen before moving on to detailed reviews of recent research in the solid chemical storage of hydrogen, and so provide an entry point for the interested reader on these diverse topics. The subjects covered include: the mechanisms of Ti catalysis in alanates; the kinetics of the borohydrides and the resulting limitations; novel transition metal catalysts for use with complex hydrides; less common borohydrides; protic-hydridic stores; metal ammines and novel approaches to nano-confined metal hydrides.
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Affiliation(s)
- Andrew J Churchard
- Interdisciplinary Centre for Mathematical and Computational Modelling, The University of Warsaw, Pawińskiego 5a, 02106 Warsaw, Poland.
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