Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Workflows in ComputationalHeterogeneous Catalysis

Antonio M. Marquez

Departamento de Quımica Fısica

Universidad de Sevilla

11 de diciembre de 2006

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Summary

1 InfrastructureHardwareSoftwareQC packages

2 Heterogeneous Catalysis

3 Metals adsorption in oxides

4 Metal Nitrides

5 Concluding remarks

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Hardware

Beowulf type Cluster including as front-end

1 Intel based Pentium IV, @ 1.8 GHz, 1 Gb RAM

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Hardware

Beowulf type Cluster including as compute nodes

16 Intel Pentium IV, @ 2.4 GHz, 1 Gb RAM

24 Intel Pentium IV, @ 3.0-3.3 GHz, 1 Gb RAM

8 Sun V60X nodes with two Intel Xeon PentiumIV, @ 3.0 GHz, 2 Gb RAM

2 SunFire V20z Servers with two AMD dualOpteron 248 processors, @ 1 GHz, 2 Gb RAM

3 SunFire V40z Servers with four dual-coreOpteron 880 processors, @ 2.4 GHz, 16 Gb RAM

Connected by a 1 Gbit/s switched Ethernet

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Operating systems and contact

Linux Operating System

RedHat 9.0 (front-end) - to be upgraded by next

January

Fedora Core 2 (Intel Based compute nodes)

Fedora Core 4 (v20z) and 5 (v40z) 64-bits kernel

Contact person

Antonio M. Marquez ( marquez@us.es )

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Quantum Chemistry packages

In use

VASP 4.6

Crystal06

CPMD 3.11.1

HONDO

Gaussian 98 (serial version only)

To be installed

NWChem

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

QC packages

VASP

Plane-wave based code

Pseudopotentials

GGA density functionals

Ground state molecular dynamics

Good parallel efficiency up to 16 nodes (dependingon system size)

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

QC packages

Crystal06

Atom-centered gaussian basis set

RHF, B3LYP

Tools to analyze the adsorbate/substrateinteraction

Reasonable efficiency for up to 8 nodes

Post Hartree-Fock methods

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

QC packages

CPMD

Plane wave based code

Pseudopotentials

Excited state molecular dynamics

Incorporated a month ago, not fully tested

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Auxiliary programs/packages

Queue system

TORQUE: very simple instalation, only a queue on theserver, simple scheduler, home-made program used toredistribute the jobs between the compute nodes,home-made shells used to submit jobs, no graphicalinterface

F90 compiler

Intel Fortran Compiler: version 7.0 and 9.0 installed

C compiler

GNU C compiler

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Auxiliary programs/packages

MPI environment

LAM 7.1.1: good performance and well integrated withTORQUE

xmakemol

Simple graphical of molecules and solids

Open Data Explorer

Visualization of electron densities from VASPRequires data conversion and some utility program

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Software we are exploring

NWChem

GridChem

PathScale

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Catalysis

Catalysis is one of the main tools in chemicalsynthesis to the efficient conversion of rawmaterials into high added-value chemicals

Catalysis-based synthesis accounts for about 90 %of chemical processes

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Catalysis: Challenges

Develop new synthetic techniques

incorporating the approaches of other

disciplines

This includes the use of new computationaltechniques to guide synthesis by theory andmolecular modelling

Develop new catalysts and reaction systems

to prepare environmentally safe processes

This includes viable solid acid and base catalyststo replace the toxic and corrosive mineral acidsand bases

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Computational Heterogeneous Catalysis

Very complex problem both experimentally andcomputationally

Characterization of active sites is challenging

Rarely possible to perform discrete and systematicadjustement of the active sites

In the worst case the active site and/or the activephase of the catalyst is poorly characterized

Simulation allows specific questions to be askedand focus experimental work on solving particularproblems

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Metals on α-Al2O3

Metal deposition on surfaces is used to producematerials with modified surface properties

Enormous interest in heterogeneous catalysis: COoxidation, NOx reduction, hidrogenation, olefinepolimerization, . . .

Aluminum oxide is particularly importantsubstrate: mechanical and thermal resistance,highly dispersed powder

Many phases exists: α-Al2O3 is the bestcharacterized and very well studied

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Metals on α-Al2O3

Adsorption of transition metals on aluminaextensively studied

Catalytic properties influenced by

Electronic structure of the atom(s) at the surfaceCluster size effects

Bonding features of single atoms and smallclusters interacting with metal oxide surfaces areof interest

Amount and direction of charge transfer at theinterfase

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Metals on α-Al2O3

Strong relaxation at thesurface (requieres PCBcode)

Many possible adsorptionsites

In depth analysys of thebonding situation requires

Analysis of DOSextracted from periodiccalculationsExamination of DensityDifference mapsCluster models to allowfor more sophisticatedbonding analysis tools

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Coinage metal atoms on α-Al2O3

Change of preferred adsorption site

Cu and Ag prefer Al-hollow siteAu prefers on-top O site

Weak interaction energies (-0.6 to -1.1 eV),following the order Cu ¿ Au ¿ Ag

Strong effect of surface relaxation (up to 30 % ofbinding energy)

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Coinage metal atoms on α-Al2O3

Bonding analysis from CSOV indicates change ofbonding mechanism

N.C.Hernandez, J. Graciani, A, Marquez and J.Fernandez Sanz,

Surf. Sci. 2005, 575, 189

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Bonding analysis: tools

Constrained Space Orbital Variations (CSOV) method

allows to partition the adsorbate/substrateinteraction into physically meaningfull interactions

Limited to orbital based approaches

HONDO: requires development of a cluster modelfor the system of interest, not allways evident

Crystal: very recent implementation of PBCapproachN.C.Hernandez, J.Fernandez Sanz, C.M. Zicovich-Wilson,

J. Chem. Phys., 2006, 124, 194105

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Next steps

Metal cluster deposition

Dynamics: cluster grow mechanism, incorporationof metal atoms into the subsurface

Reactivity: CO oxidation

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Metals nitrides and oxides

Early transition metal nitrides show an unusualcombination of metallic, covalent and ionicproperties

High termal and mechanical resistance

High electronic conductivity: they are metals

All those properties may change dramatically withthe oxidation process

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Metals nitrides and oxidesComputationally challenging

Very important rippling atthe surface

Requires a large model tobe reproduced

Metal character best suitedto be reproduced withplane-wave codes

Presence of defects and localoxidation process best to bedeal with MO based codes

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Deposition of O2 on TiN and ScN

O2 adsorbs molecularly in different sites

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Deposition of O2 on TiN and ScN

O2 dissociation is easy

further incorporation of O atoms into the subsurface isdifficult

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Next steps

Surface oxidation: in colaboration with BNL

TiON phases or TiO + TiN segregated phases ?

Metal deposition on TiN (on going work)

Metal deposition on oxided phases

Workflows in

Computational

Heterogeneous

Catalysis

Infrastructure

Heterogeneous

Catalysis

Metals adsorption

in oxides

Metal Nitrides

Concluding remarks

Concluding remarks

Computational Heterogeneous Catalysis is a complexsubject that requires

Computationally intensive applications

Sophisticated tools to analyze bonding interactions

Interplay of many applications transferingstructure, and electron density data

Manipulation of many files by the user, storageand retrieval of results

Generation of many different structures incomplex problems