%0 Journal Article %1 Mhadeshwar2003 %A Mhadeshwar, A. B. %A Wang, H. %A Vlachos, D. G. %D 2003 %J Journal of Physical Chemistry B %K ACTIVATION AMMONIA-SYNTHESIS; BARRIERS; CATALYTIC-REACTIONS; CO ETHYLENE FIRST-PRINCIPLES; HYDROGENATION; INTRINSIC METAL-SURFACES MONTE-CARLO-SIMULATION; OXIDATION; SHIFT; TEMPERATURE-DEPENDENCE; WATER-GAS %N 46 %P 12721-12733 %T Thermodynamic consistency in microkinetic development of surface reaction mechanisms %U <Go to ISI>://000186574500028 %V 107 %X The foundation of microkinetic analysis over 10 years ago has drastically changed the way of parametrization of rates of surface-catalyzed reactions. In the initial stages of development, some parameters arose from experimental data whereas others were fitted to experimental data. Semiempirical and first principles quantum mechanical and statistical mechanics simulations nowadays are powerful tools in estimating kinetic parameters. However, even in best cases, some tuning of parameters is typically necessary for quantitative model predictions. During this process, parameters of reaction mechanisms may violate thermodynamics. Here we review thermodynamic constraints of reaction networks and derive expressions applicable to surface reactions. We present three examples of ethylene hydrogenation, ammonia synthesis, and hydrogen oxidation to assess the thermodynamic validity of literature mechanisms. Various methods to ensure thermodynamic consistency are discussed and demonstrated with a specific example of H-2 oxidation on Pt. The use of semiempirical techniques, such as the bond order conservation (BOC), known also as unity bond index-quadratic exponential potential (UBI-QEP) or Polanyi free energy relations, and first principles density functional theory (DFT), in conjunction with fitting of experimental data is discussed. Finally, mechanisms compatible with Surface CHEMKIN are proposed.

@article{Mhadeshwar2003, abstract = {The foundation of microkinetic analysis over 10 years ago has drastically changed the way of parametrization of rates of surface-catalyzed reactions. In the initial stages of development, some parameters arose from experimental data whereas others were fitted to experimental data. Semiempirical and first principles quantum mechanical and statistical mechanics simulations nowadays are powerful tools in estimating kinetic parameters. However, even in best cases, some tuning of parameters is typically necessary for quantitative model predictions. During this process, parameters of reaction mechanisms may violate thermodynamics. Here we review thermodynamic constraints of reaction networks and derive expressions applicable to surface reactions. We present three examples of ethylene hydrogenation, ammonia synthesis, and hydrogen oxidation to assess the thermodynamic validity of literature mechanisms. Various methods to ensure thermodynamic consistency are discussed and demonstrated with a specific example of H-2 oxidation on Pt. The use of semiempirical techniques, such as the bond order conservation (BOC), known also as unity bond index-quadratic exponential potential (UBI-QEP) or Polanyi free energy relations, and first principles density functional theory (DFT), in conjunction with fitting of experimental data is discussed. Finally, mechanisms compatible with Surface CHEMKIN are proposed.}, added-at = {2007-11-22T09:11:49.000+0100}, author = {Mhadeshwar, A. B. and Wang, H. and Vlachos, D. G.}, biburl = {https://www.bibsonomy.org/bibtex/27c9e3a0998117eb61b5d4e60a5f3bc7d/tboehme}, endnotereftype = {Journal Article}, interhash = {ce3b38a7586f15ccccdd6d1e4e1656f3}, intrahash = {7c9e3a0998117eb61b5d4e60a5f3bc7d}, journal = {Journal of Physical Chemistry B}, keywords = {ACTIVATION AMMONIA-SYNTHESIS; BARRIERS; CATALYTIC-REACTIONS; CO ETHYLENE FIRST-PRINCIPLES; HYDROGENATION; INTRINSIC METAL-SURFACES MONTE-CARLO-SIMULATION; OXIDATION; SHIFT; TEMPERATURE-DEPENDENCE; WATER-GAS}, month = Nov, number = 46, pages = {12721-12733}, shorttitle = {Thermodynamic consistency in microkinetic development of surface reaction mechanisms}, timestamp = {2007-11-22T09:12:03.000+0100}, title = {Thermodynamic consistency in microkinetic development of surface reaction mechanisms}, url = {<Go to ISI>://000186574500028 }, volume = 107, year = 2003 }