Mechanism of Hydrogen Spillover on WO3(001) and Formation of HxWO3 (x = 0.125, 0.25, 0.375, and 0.5)

Hydrogen spillover onto the WO3(001) surface and further into the bulk in the presence of a platinum catalyst was investigated by density functional theory calculations. The diffusion pathways are designed based on the energetic preference of hydrogen adsorption. Atomic H migrates from a platinum catalyst, where it is adsorbed upon H2 dissociative chemisorption, to terminal oxygen on WO3 (001) surface, followed by migration to in-plane oxygen and then diffusion across the surface or insertion in the lattice. We first theoretically corroborated the role of water in facilitating the hydrogen spillover process. The otherwise prohibitively high activation barriers were considerably reduced with the participation of water, which agrees well with experimental facts. The high mobility of H inside the WO3 lattice was also identified with low calculated diffusion barriers for several selected migration pathways. Finally, the effects of hydrogen concentration and electronic structures of HxWO3 were investigated. Th...

[1]  E. Gaudin,et al.  Formation of tetragonal hydrogen tungsten bronze by reactive mechanical alloying , 2007 .

[2]  Hansong Cheng,et al.  Hydrogen spillover in the context of hydrogen storage using solid-state materials , 2008 .

[3]  P. Dickens,et al.  Hydrogen insertion compounds of transition metal oxides , 1981 .

[4]  G. Kresse,et al.  From ultrasoft pseudopotentials to the projector augmented-wave method , 1999 .

[5]  G. Henkelman,et al.  A climbing image nudged elastic band method for finding saddle points and minimum energy paths , 2000 .

[6]  H. Hosono,et al.  Formation of hydrogen tungsten bronze by proton implantation , 1999 .

[7]  S. Khoobiar.  Particle to Particle Migration of Hydrogen Atoms on Platinum—Alumina Catalysts from Particle to Neighboring Particles , 1964 .

[8]  P. Sermon,et al.  Reversible isothermal sorption of hydrogen by tungsten trioxide in presence of platinum , 1983, Nature.

[9]  Fenggong Wang,et al.  DFT Study of Hydrogen Adsorption On the Monoclinic WO3 (001) Surface , 2012 .

[10]  Hansong Cheng,et al.  Hydrogen Absorption and Diffusion in Bulk α-MoO3 , 2009 .

[11]  G. Henkelman,et al.  A fast and robust algorithm for Bader decomposition of charge density , 2006 .

[12]  R. T. Yang,et al.  Enhanced Hydrogen Spillover on Carbon Surfaces Modified by Oxygen Plasma , 2010 .

[13]  Blöchl,et al.  Projector augmented-wave method. , 1994, Physical review. B, Condensed matter.

[14]  P. Wiseman,et al.  The crystal structure of cubic hydrogen tungsten bronze , 1973 .

[15]  U. Roland,et al.  On the nature of spilt-over hydrogen , 1997 .

[16]  M. Boudart,et al.  The kinetics and mechanism of spillover , 1974 .

[17]  Carrie A. Farberow,et al.  Water-Mediated Proton Hopping on an Iron Oxide Surface , 2012, Science.

[18]  H. Rietveld,et al.  Further refinement of the structure of WO3 , 1969 .

[19]  Gunnar A. Niklasson,et al.  Electrochromics for smart windows: thin films of tungsten oxide and nickel oxide, and devices based on these , 2007 .

[20]  Satyen K. Deb,et al.  Opportunities and challenges in science and technology of WO3 for electrochromic and related applications , 2008 .

[21]  R. Prins,et al.  Behavior of Ti3+ centers in the low- and high-temperature reduction of Pt/TiO2, studied by ESR , 1981 .

[22]  L. Bartha,et al.  Chemistry of tungsten oxide bronzes , 1995 .

[23]  P. Dickens,et al.  X-ray and Neutron Diffraction Studies of a Tetragonal Hydrogen Bronze HxWO3 , 1967, Nature.

[24]  Ivo Jakubec,et al.  The accelerating role of water in hydrogen insertion into tungsten trioxide , 1999 .

[25]  Yanfa Yan,et al.  Density-functional theory study of the effects of atomic impurity on the band edges of monoclinic WO3 , 2008 .

[26]  Omar M Yaghi,et al.  Strategies for hydrogen storage in metal--organic frameworks. , 2005, Angewandte Chemie.

[27]  John L. Falconer,et al.  Spillover in Heterogeneous Catalysis , 1995 .

[28]  I. R. Harris,et al.  Hydrogen storage in ion-exchanged zeolites , 2005 .

[29]  Edward Sanville,et al.  Improved grid‐based algorithm for Bader charge allocation , 2007, J. Comput. Chem..

[30]  Burke,et al.  Generalized Gradient Approximation Made Simple. , 1996, Physical review letters.

[31]  Kresse,et al.  Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. , 1996, Physical review. B, Condensed matter.

[32]  J. Vondrak,et al.  The Role of Water in Hydrogen Insertion into WO3 , 1994 .

[33]  P. Dickens,et al.  The tungsten bronzes and related compounds , 1968 .

[34]  M. Vannice,et al.  Mobility of hydrogen in hydrogen tungsten bronze , 1970 .

[35]  Anthony J. Lachawiec,et al.  Reverse spillover of hydrogen on carbon-based nanomaterials: evidence of recombination using isotopic exchange , 2009 .

[36]  G. Bond,et al.  Studies of hydrogen spillover. Part 4.—Factors affecting hydrogen spillover and its reversal , 1980 .

[37]  S. C. Parker,et al.  Computer simulation of the surface structures of WO3 , 1996 .

[38]  R. C. Forrey,et al.  On the Sequential Hydrogen Dissociative Chemisorption on Small Platinum Clusters: A Density Functional Theory Study , 2007 .

[39]  R. Prins.  Hydrogen spillover. Facts and fiction. , 2012, Chemical reviews.

[40]  G. Kresse,et al.  Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set , 1996 .

[41]  P. Dickens,et al.  Electrochemical Insertion of Hydrogen in WO 3 , 1982 .

[42]  J. E. Benson,et al.  On the reduction of tungsten trioxide accelerated by platinum and water , 1966 .

[43]  H. Monkhorst,et al.  SPECIAL POINTS FOR BRILLOUIN-ZONE INTEGRATIONS , 1976 .

[44]  Fenggong Wang,et al.  Electronic and Structural Properties of WO3: A Systematic Hybrid DFT Study , 2011 .

[45]  F. Castro,et al.  Synthesis of hydrogen tungsten bronzes HxWO3 by reactive mechanical milling of hexagonal WO3 , 2010 .

[46]  P. Dickens,et al.  Thermochemistry of hydrogen tungsten bronze phases HxWO3 , 1973 .

[47]  Donghai Mei,et al.  Reactivity of Hydrogen and Methanol on (001) Surfaces of WO3, ReO3, WO3/ReO3 and ReO3/WO3 , 2011 .

[48]  Hansong Cheng,et al.  On the Mechanisms of Hydrogen Spillover in MoO3 , 2008 .

[49]  M. Whittingham.  Hydrogen motion in oxides: from insulators to bronzes , 2004 .