CO oxidation on stepped single crystal electrodes: A dynamic Monte Carlo study

Mechanisms of Carbon Monoxide and Methanol Oxidation at Single-crystal Electrodes

“…Therefore, this model implies that specific anion adsorption can affect the dynamics of the CO electrooxidation reaction, shifting the mechanism from a mean field approximation to a nucleation-and-growth model with increasing anion adsorption strength. Dynamic Monte Carlo simulations with varying diffusion rates were found to be in agreement with this model [36].…”

Methanol, Formaldehyde, and Formic Acid Adsorption/Oxidation on a Carbon‐Supported Pt Nanoparticle Fuel Cell Catalyst: A Comparative Quantitative DEMS Study

“…It is generally agreed (for carbon-supported Pt/C catalysts, see [Friedrich et al, 2000;Maillard et al, 2004aMaillard et al, , 2005Arenz et al, 2005;Andreaus et al, 2006;Andreaus and Eikerling, 2007]; for smooth Pt electrodes, see [Santos et al, 1991;Petukhov et al, 1998;Koper et al, 1998;Bergelin et al, 1999;Korzeniewski and Kardash, 2001;Lebedeva et al, 2002;Housmans et al, 2007]) that electro-oxidation of adsorbed CO on Pt electrodes proceeds via a LangmuirHinshelwood mechanism by reaction between CO ad and neighboring, electrosorbed OH ad species. In the initial peak, this includes initial (instantaneous) nucleation of OH ad , possibly on defect sites, reaction with weakly bound CO ad species, and slow relaxation of the CO adlayer into a more strongly bound state.…”

“…An increasingly faster onset of the main oxidation peak for transient C 1 adsorbate oxidation with decreasing CO ad coverage would be consistent with a Langmuir -Hinshelwood mechanism, since nucleation of OH ad should become more facile at lower CO ad coverages, which in turn increases the adlayer oxidation rate and shifts the main oxidation peak towards the initial spike. The asymmetric shape of the initial peak with a significant tailing at longer times can be explained by the increasing overlap of the initial "instantaneous" OH ad nucleation and reaction step [Korzeniewski and Kardash, 2001], and CO 2 formation via progressive OH ad nucleation and reaction with CO ad [Lebedeva et al, 2000[Lebedeva et al, , 2002Andreaus and Eikerling, 2007;Housmans et al, 2007].…”

ATR-SEIRAS study of CO adsorption and oxidation on Rh modified Au(111-25 nm) film electrodes in 0.1 M H2SO4

“…Gómez et al [16] studied the role of surface heterogeneities (ordered steps and defects) on the oxidation of CO adsorbed at Rh (111) electrodes and found that the more ordered is the Rh(111) surface, the slower the reaction proceeds. Housmanns et al investigated CO electro-oxidation on "ordered" and "disordered" Rh[n(111)-(111)] single crystal electrodes [17][18][19][20][21] and proposed that the CO electro-oxidation follows a Langmuir-Hinshelwood type nucleation and growth mechanism controlled by the slow surface mobility of adsorbed CO. Anions were also shown to play an important role in the CO oxidation mechanism on Rh electrodes [19]. In our electrochemical study of the three low-index Rh single crystal surfaces [22] we demonstrated that the reaction pathway of CO oxidation on all three low-index Rh surfaces proceeds according to the Langmuir-Hinshelwood mechanism and is controlled by the formation of OH ads at steps and defect sites, followed by a complex growth process on terrace sites.…”