Synthesis and decomposition of formate on a Cu(111) surface — kinetic analysis

Nishimura, Hirokazu; Yatsu, T.; Fujitani, Tadahiro; Uchijima, Toshio; Nakamura, Junji

doi:10.1016/s1381-1169(99)00314-3

Cited by 31 publications

(47 citation statements)

References 39 publications

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“…This effect has been proposed recently for behavior of Pt-CeO 2 system in the reverse water-gas shift reaction [34,35]. The results in reference [33] showing that formate decomposes more rapidly on O-precovered Cu(111) are also consistent with this interpretation. Whatever the source of the effect, the changes to the surface coverages occur promptly with the change in gas atmosphere.…”

Section: Resultssupporting

confidence: 76%

“…The rates of DCOO decomposition in this study fall on the low side of the band because of this kinetic isotope effect. In addition to the structure sensitivity evident in these data, a sensitivity to surface composition is evident not only in the hydrogen promotion results, but also in reports that formate prepared from formic acid on O-precovered Cu(111) decomposes more rapidly than that prepared from CO 2 and H 2 [33].…”

Section: Resultsmentioning

confidence: 70%

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Simultaneous MS-IR Studies of Surface Formate Reactivity Under Methanol Synthesis Conditions on Cu/SiO2

et al. 2009

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The coverages and surface lifetimes of copperbound formates on Cu/SiO 2 catalysts, and the steady-state rates of reverse water-gas shift and methanol synthesis have been measured simultaneously by mass (MS) and infrared (IR) spectroscopies under a variety of elevated pressure conditions at temperatures between 140 and 160°C. DCOO lifetimes under steady state catalytic conditions in CO 2 :D 2 atmospheres were measured by 12 C-13 C isotope transients (SSITKA). The values range from 220 s at 160°C to 660 s at 140°C. The catalytic rates of both reverse water gas shift (RWGS) and methanol synthesis are *100-fold slower than this formate removal rate back to CO 2 ? 1/2 H 2 , and thus they do not significantly influence the formate lifetime or coverage at steady state. The formate coverage is instead determined by formate's rapid production/decomposition equilibrium with gas phase CO 2 ? H 2 . The results are consistent with formate being an intermediate in methanol synthesis, but with the ratecontrolling step being after formate production (for example, its further hydrogenation to methoxy). A 2-3 fold shorter life time (faster decomposition rate) was observed for formate under reactions conditions, with both D 2 and CO 2 present, than in pure Ar or D 2 ? Ar alone. This effect, due in part to the effects of the coadsorbates produced under reaction conditions, illustrates the importance of using in situ techniques in the study of catalytic mechanisms. The carbon which appears in the methanol product spends a longer time on the surface than the formate species, 1.8 times as long at 140°C. The additional delay on the surface is attributed in part to readsorption of methanol on the catalyst, thus obscuring the mechanistic link between formate and methanol.

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Section: Resultssupporting

confidence: 76%

Section: Resultsmentioning

confidence: 70%

Simultaneous MS-IR Studies of Surface Formate Reactivity Under Methanol Synthesis Conditions on Cu/SiO2

et al. 2009

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“…The formate decomposes to desorb CO 2 and hydrogen coincidently with a peak rate at $460 K, and is a rare example of a classical firstorder decomposition, at least at coverages up to $0.25 ML [9][10][11][12]14,20]. STM studies have shown that the formate can form both 0.5 ML c(2 Â 2) structures and a high coverage (0.67 ML) (3 Â 1) structure [14,[16][17][18][19][20]24,26]. The latter is seen when formic acid reacts with >0.25 ML coverage of O atoms.…”

Section: Introductionmentioning

confidence: 99%

“…Some complications appear to arise in the TPD at high formate coverages (for instance, when dosed onto 0.5 ML precoverage of atomic oxygen) where there is evidence of a low-temperature shoulder in the TPD [14,20]. The kinetics are much more complicated for the surface with 0.5 ML of oxygen present due to gross rearrangement of the metal surface [19,20,26] and this regime of reactivity will not be dealt with here. In this paper we wish to concentrate on the oxidation of formic acid on Cu(1 1 0).…”

Section: Introductionmentioning

confidence: 99%

Formic acid adsorption and oxidation on Cu(110)

2008

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“…[1][2][3][4][5] Based on a kinetics analysis, it was clarified that formate synthesis is structure insensitive and consistent with an Eley-Rideal (ER) type mechanism. [6][7][8][9] Recently, theoretical investigations also suggested the ER and hot atom (HA) mechanisms during CO 2 reduction into formate and/or hydrocarboxyl (HOCO). 10 The ER type mechanism suggests that the formate synthesis can be enhanced by controlling the translational, vibrational, and rotational energies of impinging CO 2 .…”

mentioning

confidence: 99%

Desorption dynamics of CO₂ from formate decomposition on Cu(111)

et al. 2017

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We performed ab initio molecular dynamics analysis of formate decomposition to CO and H on a Cu(111) surface using van der Waals density functionals. Our analysis shows that the desorbed CO has approximately twice larger bending vibrational energy than the translational, rotational, and stretching vibrational energies. Since formate synthesis, the reverse reaction of formate decomposition, has been suggested experimentally to occur via the Eley-Rideal mechanism, our results indicate that the formate synthesis can be enhanced if the bending vibrational mode of CO is excited rather than the translational and/or stretching vibrational modes. Detailed information on the energy distribution of desorbed CO as a formate decomposition product may provide new insights for improving the catalytic activity of formate synthesis.

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Synthesis and decomposition of formate on a Cu(111) surface — kinetic analysis

Cited by 31 publications

References 39 publications

Simultaneous MS-IR Studies of Surface Formate Reactivity Under Methanol Synthesis Conditions on Cu/SiO2

Simultaneous MS-IR Studies of Surface Formate Reactivity Under Methanol Synthesis Conditions on Cu/SiO2

Formic acid adsorption and oxidation on Cu(110)

Desorption dynamics of CO₂ from formate decomposition on Cu(111)

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Synthesis and decomposition of formate on a Cu(111) surface — kinetic analysis

Cited by 31 publications

References 39 publications

Simultaneous MS-IR Studies of Surface Formate Reactivity Under Methanol Synthesis Conditions on Cu/SiO2

Simultaneous MS-IR Studies of Surface Formate Reactivity Under Methanol Synthesis Conditions on Cu/SiO2

Formic acid adsorption and oxidation on Cu(110)

Desorption dynamics of CO2 from formate decomposition on Cu(111)

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Desorption dynamics of CO₂ from formate decomposition on Cu(111)