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Qiu M, Li Y, Zhang Y. The mechanism for CO 2 reduction over Fe-modified Cu(100) surfaces with thermodynamics and kinetics: a DFT study. RSC Adv 2020; 10:32569-32580. [PMID: 35516500 PMCID: PMC9056627 DOI: 10.1039/d0ra06319c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 08/24/2020] [Indexed: 11/23/2022] Open
Abstract
The adsorption, activation and reduction of CO2 over Fex/Cu(100) (x = 1–9) surfaces were examined by density functional theory. The most stable structure of CO2 adsorption on the Fex/Cu(100) surface was realized. The electronic structure analysis showed that the doped Fe improved the adsorption, activation and reduction of CO2 on the pure Cu(100) surface. From the perspective of thermodynamics and kinetics, the Fe4/Cu(100) surface acted as a potential catalyst to decompose CO2 into CO with a barrier of 32.8 kJ mol−1. Meanwhile, the first principle molecular dynamics (FPMD) analysis indicated that the decomposition of the C–O1 bond of CO2 on the Fe4/Cu(100) surface was only observed from 350 K to 450 K under a CO2 partial pressure from 0 atm to 10 atm. Furthermore, the results of FPMD analysis revealed that CO2 would rather decompose than hydrogenate when CO2 and H co-adsorbed on the Fe4/Cu(100) surface. The adsorption, activation and reduction of CO2 over Fex/Cu(100) (x = 1–9) surfaces were examined by density functional theory.![]()
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Affiliation(s)
- Mei Qiu
- Department of Chemistry, College of Science, Jiangxi Agricultural University Nanchang Jiangxi 330045 China .,State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences 350002 Fuzhou Fujian 350002 China
| | - Yi Li
- College of Chemistry, Fuzhou University Fuzhou Fujian 350116 China
| | - Yongfan Zhang
- College of Chemistry, Fuzhou University Fuzhou Fujian 350116 China
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German ED. Theoretical models of X–H bonds breaking (X = C, O, and H) over metal surfaces: Used for simulation of catalytic methane steam reforming. RUSS J ELECTROCHEM+ 2017. [DOI: 10.1134/s1023193517100044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Octahedral Ni-nanocluster (Ni85) for Efficient and Selective Reduction of Nitric Oxide (NO) to Nitrogen (N2). Sci Rep 2016; 6:25590. [PMID: 27157072 PMCID: PMC4860637 DOI: 10.1038/srep25590] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 04/11/2016] [Indexed: 01/06/2023] Open
Abstract
Nitric oxide (NO) reduction pathways are systematically studied on a (111) facet of the octahedral nickel (Ni85) nanocluster in the presence/absence of hydrogen. Thermodynamic (reaction free energies) and kinetic (free energy barriers, and temperature dependent reaction rates) parameters are investigated to find out the most favoured reduction pathway for NO reduction. The catalytic activity of the Ni-nanocluster is investigated in greater detail toward the product selectivity (N2 vs. N2O vs. NH3). The previous theoretical (catalyzed by Pt, Pd, Rh and Ir) and experimental reports (catalyzed by Pt, Ag, Pd) show that direct N-O bond dissociation is very much unlikely due to the high-energy barrier but our study shows that the reaction is thermodynamically and kinetically favourable when catalysed by the octahedral Ni-nanocluster. The catalytic activity of the Ni-nanocluster toward NO reduction reaction is very much efficient and selective toward N2 formation even in the presence of hydrogen. However, N2O (one of the major by-products) formation is very much unlikely due to the high activation barrier. Our microkinetic analysis shows that even at high hydrogen partial pressures, the catalyst is very much selective toward N2 formation over NH3.
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Donald SB, Navin JK, Harrison I. Methane dissociative chemisorption and detailed balance on Pt(111): dynamical constraints and the modest influence of tunneling. J Chem Phys 2014; 139:214707. [PMID: 24320394 DOI: 10.1063/1.4837697] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A dynamically biased (d-) precursor mediated microcanonical trapping (PMMT) model of the activated dissociative chemisorption of methane on Pt(111) is applied to a wide range of dissociative sticking experiments, and, by detailed balance, to the methane product state distributions from the thermal associative desorption of adsorbed hydrogen with coadsorbed methyl radicals. Tunneling pathways were incorporated into the d-PMMT model to better replicate the translational energy distribution of the desorbing methane product from the laser induced thermal reaction of coadsorbed hydrogen and methyl radicals occurring near T(s) = 395 K. Although tunneling is predicted to be inconsequential to the thermal dissociative chemisorption of CH4 on Pt(111) at the high temperatures of catalytic interest, once the temperature drops to 395 K the tunneling fraction of the reactive thermal flux reaches 15%, and as temperatures drop below 275 K the tunneling fraction exceeds 50%. The d-PMMT model parameters of {E0 = 58.9 kJ/mol, s = 2, η(v) = 0.40} describe the apparent threshold energy for CH4/Pt(111) dissociative chemisorption, the number of surface oscillators involved in the precursor complex, and the efficacy of molecular vibrational energy to promote reaction, relative to translational energy directed along the surface normal. Molecular translations parallel to the surface and rotations are treated as spectator degrees of freedom. Transition state vibrational frequencies are derived from generalized gradient approximation-density functional theory electronic structure calculations. The d-PMMT model replicates the diverse range of experimental data available with good fidelity, including some new effusive molecular beam and ambient gas dissociative sticking measurements. Nevertheless, there are some indications that closer agreement between theory and experiments could be achieved if a surface efficacy less than one was introduced into the modeling as an additional dynamical constraint.
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Affiliation(s)
- S B Donald
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA
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Navin JK, Donald SB, Tinney DG, Cushing GW, Harrison I. Communication: Angle-resolved thermal dissociative sticking of CH4 on Pt(111): Further indication that rotation is a spectator to the gas-surface reaction dynamics. J Chem Phys 2012; 136:061101. [DOI: 10.1063/1.3685833] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- J. K. Navin
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA
| | - S. B. Donald
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA
| | - D. G. Tinney
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA
| | - G. W. Cushing
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA
| | - I. Harrison
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA
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Donald SB, Harrison I. Dynamically biased RRKM model of activated gas-surface reactivity: vibrational efficacy and rotation as a spectator in the dissociative chemisorption of CH4on Pt(111). Phys Chem Chem Phys 2012; 14:1784-95. [DOI: 10.1039/c2cp22895e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Cushing GW, Navin JK, Valadez L, Johánek V, Harrison I. An effusive molecular beam technique for studies of polyatomic gas-surface reactivity and energy transfer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:044102. [PMID: 21529024 DOI: 10.1063/1.3577076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
An effusive molecular beam technique is described to measure alkane dissociative sticking coefficients, S(T(g), T(s); ϑ), on metal surfaces for which the impinging gas temperature, T(g), and surface temperature, T(s), can be independently varied, along with the angle of incidence, ϑ, of the impinging gas. Effusive beam experiments with T(g) = T(s) = T allow for determination of angle-resolved dissociative sticking coefficients, S(T; ϑ), which when averaged over the cos (ϑ)/π angular distribution appropriate to the impinging flux from a thermal ambient gas yield the thermal dissociative sticking coefficient, S(T). Nonequilibrium S(T(g), T(s); ϑ) measurements for which T(g) ≠ T(s) provide additional opportunities to characterize the transition state and gas-surface energy transfer at reactive energies. A resistively heated effusive molecular beam doser controls the T(g) of the impinging gas striking the surface. The flux of molecules striking the surface from the effusive beam is determined from knowledge of the dosing geometry, chamber pressure, and pumping speed. Separate experiments with a calibrated leak serve to fix the chamber pumping speed. Postdosing Auger electron spectroscopy is used to measure the carbon of the alkyl radical reaction product that is deposited on the surface as a result of alkane dissociative sticking. As implemented in a typical ultrahigh vacuum chamber for surface analysis, the technique has provided access to a dynamic range of roughly 6 orders of magnitude in the initial dissociative sticking coefficient for small alkanes on Pt(111).
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Affiliation(s)
- G W Cushing
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA
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An W, Zeng XC, Turner CH. First-principles study of methane dehydrogenation on a bimetallic Cu/Ni(111) surface. J Chem Phys 2009; 131:174702. [DOI: 10.1063/1.3254383] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abbott HL, Harrison I. Microcanonical Transition State Theory for Activated Gas−Surface Reaction Dynamics: Application to H2/Cu(111) with Rotation as a Spectator. J Phys Chem A 2007; 111:9871-83. [PMID: 17845015 DOI: 10.1021/jp074038a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A microcanonical unimolecular rate theory (MURT) model incorporating quantized surface vibrations and Rice-Ramsperger-Kassel-Marcus rate constants is applied to a benchmark system for gas-surface reaction dynamics, the activated dissociative chemisorption and associative desorption of hydrogen on Cu(111). Both molecular translation parallel to the surface and rotation are treated as spectator degrees of freedom. MURT analysis of diverse experiments indicates that one surface oscillator participates in the dissociative transition state and that the threshold energy for H2 dissociation on Cu(111) is E0 = 62 kJ/mol. The spectator approximation for rotation holds well at thermally accessible rotational energies (i.e., for Er less than approximately 40 kJ/mol). Over the temperature range from 300 to 1000 K, the calculated thermal dissociative sticking coefficient is ST = S0 exp(-Ea/kBT) where S0 = 1.57 and Ea = 62.9 kJ/mol. The sigmoid shape of rovibrational eigenstate-resolved dissociative sticking coefficients as a function of normal translational energy is shown to derive from an averaging of the microcanonical sticking coefficient, with threshold energy E0, over the thermal surface oscillator distribution of the gas-surface collision complexes. Given that H2/Cu(111) is one of the most dynamically biased of gas-surface reactive systems, the simple statistical MURT model simulates and broadly rationalizes the H2/Cu(111) reactive behavior with remarkable fidelity.
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Affiliation(s)
- Heather L Abbott
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA
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Psofogiannakis G, St-Amant A, Ternan M. Methane oxidation mechanism on Pt(111): a cluster model DFT study. J Phys Chem B 2007; 110:24593-605. [PMID: 17134220 DOI: 10.1021/jp061559+] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The electronic energy barriers of surface reactions pertaining to the mechanism of the electrooxidation of methane on Pt (111) were estimated with density functional theory calculations on a 10-atom Pt cluster, using both the B3LYP and PW91 functionals. Optimizations of initial and transition states were performed for elementary steps that involve the conversion of CH(4) to adsorbed CO at the Pt/vacuum interface. As a first approximation we do not include electrolyte effects in our model. The reactions include the dissociative chemisorption of CH(4) on Pt, dehydrogenation reactions of adsorbed intermediates (*CH(x) --> *CH(x-1) + *H and *CH(x)O --> *CH(x-1)O + *H), and oxygenation reactions of adsorbed CH(x) species (*CH(x) + *OH --> *CH(x)OH). Many pathways were investigated and it was found that the main reaction pathway is CH(4) --> *CH(3) --> *CH(2) --> *CH --> *CHOH --> *CHO --> *CO. Frequency analysis and transition-state theory were employed to show that the methane chemisorption elementary step is rate-limiting in the above mechanism. This conclusion is in agreement with published experimental electrochemical studies of methane oxidation on platinum catalysts that have shown the absence of an organic adlayer at electrode potentials that allow the oxidation of adsorbed CO. The mechanism of the electrooxidation of methane on Pt is discussed.
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Affiliation(s)
- George Psofogiannakis
- Department of Chemical Engineering and Department of Chemistry, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.
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Abbott HL, Harrison I. Seven-dimensional microcanonical treatment of hydrogen dissociation dynamics on Cu(111): Clarifying the essential role of surface phonons. J Chem Phys 2006; 125:24704. [PMID: 16848601 DOI: 10.1063/1.2208362] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A simple picture of the hydrogen dissociation/associative desorption dynamics on Cu(111) emerges from a two-parameter, full dimensionality microcanonical unimolecular rate theory (MURT) model of the gas-surface reactivity. Vibrational frequencies for the reactive transition state were taken from density functional theory calculations of a six-dimensional potential energy surface [Hammer et al., Phys. Rev. Lett. 73, 1400 (1994)]. The two remaining parameters required by the MURT were fixed by simulation of experiments. These parameters are the dissociation threshold energy, E(0)=79 kJmol, and the number of surface oscillators involved in the localized H(2)Cu(111) collision complex, s=1. The two-parameter MURT quantitatively predicts much of the varied behavior observed for the H(2) and D(2)Cu(111) reactive systems, including the temperature-dependent associative desorption angular distributions, mean translational energies of the associatively desorbing hydrogen as a function of rovibrational eigenstate, etc. The divergence of the statistical theory's predictions from experimental results at low rotational quantum numbers, J < or approximately 5, suggests that either (i) rotational steering is important to the dissociation dynamics at low J, an effect that washes out at high J, or (ii) molecular rotation is approximately a spectator degree of freedom to the dissociation dynamics for these low J states, the states that dominate the thermal reactivity. Surface vibrations are predicted to provide approximately 30% of the energy required to surmount the activation barrier to H(2) dissociation under thermal equilibrium conditions. The MURT with s=1 is used to analytically confirm the experimental finding that partial differential "E(a)(T(s))" partial differential E(t)= -1 for eigenstate-resolved dissociative sticking at translational energies E(t)<E(0)-E(v)-E(r). Explicit treatment of the surface motion (i.e., surface not frozen at T(s)=0 K) is a relatively novel aspect of the MURT theoretical approach.
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Affiliation(s)
- H L Abbott
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904-4319, USA
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Danziger IM, Asscher M. Collision-Induced Migration of Adsorbates on Solid Surfaces: An Experimental Approach. J Phys Chem A 2006; 110:8339-45. [PMID: 16821817 DOI: 10.1021/jp056839o] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Collision-induced migration (CIM) is a process in which energetic gas-phase atoms or molecules at the tail of the Boltzmann distribution enhance surface migration of adsorbates upon collision. It is believed to exist and play an important role in any realistic high pressure-high-temperature heterogeneous catalytic system. Combining supersonic beam-surface collision setup with in-situ optical second harmonic generation diffraction technique from a coverage grating, we have shown, for the first time, that indeed energetic collisions (Kr seeded in He) promote surface mobility of CO-K surface complex on Ru(001) with a threshold total kinetic energy of 3 eV. An average migration distance/collision of more than 30 adsorption sites was estimated from the experimental data at Kr total energy of 3.8 eV. This long-range migration distance per collision is understood in terms of a cascade migration mechanism, where adsorbed CO molecules collide and push their neighbors from high to low coverage areas, in a direction dictated by the collision momentum vector. A similar mechanism has recently been suggested to explain adsorbate mobility at high coverage induced by an STM tip.
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Affiliation(s)
- I M Danziger
- Department of Physical Chemistry and the Farkas Center for Light Induced Processes, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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DeWitt KM, Valadez L, Abbott HL, Kolasinski KW, Harrison I. Using Effusive Molecular Beams and Microcanonical Unimolecular Rate Theory to Characterize CH4 Dissociation on Pt(111). J Phys Chem B 2006; 110:6705-13. [PMID: 16570976 DOI: 10.1021/jp0566865] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The dissociative sticking coefficient for CH4 on Pt(111) has been measured as a function of both gas temperature (Tg) and surface temperature (Ts) using effusive molecular beam and angle-integrated ambient gas dosing methods. The experimental results are used to optimize the three parameters of a microcanonical unimolecular rate theory (MURT) model of the reactive system. The MURT calculations allow us to extract transition state properties from the data as well as to compare our data directly to other molecular beam and thermal equilibrium sticking measurements. We find a threshold energy for dissociation of E0 = 52.5 +/- 3.5 kJ mol(-1). Furthermore, the MURT with an optimized parameter set provides for a predictive understanding of the kinetics of this C-H bond activation reaction, that is, it allows us to predict the dissociative sticking coefficient of CH4 on Pt(111) for any combination of Ts and Tg even if the two are not equal to one another, indeed, the distribution of molecular energy need not even be thermal. Comparison of our results to those from recent thermal equilibrium catalysis studies on CH4 reforming over Pt nanoclusters ( approximately 2 nm diam) dispersed on oxide substrates indicates that the reactivity of Pt(111) exceeds that of the Pt nanocatalysts by several orders of magnitude.
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Affiliation(s)
- Kristy M DeWitt
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA
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DeWitt KM, Valadez L, Abbott HL, Kolasinski KW, Harrison I. Effusive Molecular Beam Study of C2H6 Dissociation on Pt(111). J Phys Chem B 2006; 110:6714-20. [PMID: 16570977 DOI: 10.1021/jp055684h] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dissociative sticking coefficient for C2H6 on Pt(111) has been measured as a function of both gas temperature (Tg) and surface temperature (Ts) using effusive molecular beam and angle-integrated ambient gas dosing methods. A microcanonical unimolecular rate theory (MURT) model of the reactive system is used to extract transition state properties from the data as well as to compare our data directly with supersonic molecular beam and thermal equilibrium sticking measurements. We report for the first time the threshold energy for dissociation, E0 = 26.5 +/- 3 kJ mol(-1). This value is only weakly dependent on the other two parameters of the model. A strong surface temperature dependence in the initial sticking coefficient is observed; however, the relatively weak dependence on gas temperature indicates some combination of the following (i) not all molecular excitations are contributing equally to the enhancement of sticking, (ii) that strong entropic effects in the dissociative transition state are leading to unusually high vibrational frequencies in the transition state, and (iii) energy transfer from gas-phase rovibrational modes to the surface is surprisingly efficient. In other words, it appears that vibrational mode-specific behavior and/or molecular rotations may play stronger roles in the dissociative adsorption of C2H6 than they do for CH4. The MURT with an optimized parameter set provides for a predictive understanding of the kinetics of this C-H bond activation reaction, that is, it allows us to predict the dissociative sticking coefficient of C2H6 on Pt(111) for any combination of Ts and Tg even if the two are not equal to one another.
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Affiliation(s)
- Kristy M DeWitt
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA
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