Reaction cycles and poisoning in catalysis by gold clusters: A thermodynamics approach. Issue 1 (2nd July 2013)

• Record Type: Journal Article
• Authors: Beret, Elizabeth C.; van, Merel M.; Ghiringhelli, Luca M.
• Is Part Of: International journal of quantum chemistry. Volume 114:Issue 1(2014:Jan. 05)
• Page Start: 57
• Page End: 65
• Publication Date: 2013-07-02
• Subjects: Quantum chemistry -- Periodicals; 541.28
• DOI: 10.1002/qua.24503
• Languages: English
• ISSNs: 0020-7608

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>In heterogeneous catalysis, a catalytic process takes place at finite temperature and at finite pressure of the atmosphere of the reactant gases. By applying <italic>ab initio</italic> atomistic thermodynamics to the model case of free Au<sub>2</sub> and <alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgg3xdzb1m2" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:00207608:media:qua24503:qua24503-math-0193" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi>Au</mml:mi><mml:mn>2</mml:mn><mml:mo>−</mml:mo></mml:msubsup></mml:mrow></mml:math></alternatives> clusters in an atmosphere of O<sub>2</sub> and CO, we derive all the thermodynamically possible reaction paths for the oxidation of CO to CO<sub>2</sub>. This analysis lets us explain how gold clusters enable oxidation reactions without breaking the spin‐conservation rule. Furthermore, we identify special cluster + ligands compositions such as reaction intermediates and poisoned species. In particular, a thermodynamically driven poisoning is identified for the catalytic system containing free Au<sub>2</sub>, and the experimental (<italic>p, T</italic>) conditions that avoid its formation are suggested. This implies that for some systems a catalytic cycle can be established, on thermodynamics grounds, only in a defined range of temperatures and pressures. In addition, our predictions for <alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgg3xdzb1kh" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:00207608:media:qua24503:qua24503-math-0194" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi>Au</mml:mi><mml:mn>2</mml:mn><mml:mo>−</mml:mo></mml:msubsup></mml:mrow></mml:math></alternatives> provide the so far most complete interpretation of the available experimental data (Socaciu et al, J. Am. Chem. Soc. 2003). © 2013 Wiley Periodicals, Inc.</p> </abstract>