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Correction: A quantum chemical study of hydrogen adsorption on carbon-supported palladium clusters

Lisa Warczinski * and Christof Hättig
Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany. E-mail: lisa.warczinski@rub.de

Received 25th March 2020 , Accepted 25th March 2020

First published on 3rd April 2020


Abstract

Correction for ‘A quantum chemical study of hydrogen adsorption on carbon-supported palladium clusters’ by Lisa Warczinski et al., Phys. Chem. Chem. Phys., 2019, 21, 21577–21587, DOI: 10.1039/c9cp04606b.


We correct an error to our previous paper,1 which does not affect the key statements of the paper but changes some values and one minor conclusion. In our previous paper, the calculation of the Gibbs free enthalpies was missing electronic contributions and an incorrect scaling parameter for the vibrational frequencies was used. Here, we report the corrected values for the Gibbs free enthalpies including all necessary contributions and employing the correct vibrational frequency scaling parameter of 1.0190 for the def2-SVP basis set and the TPSS functional.2

The first values we need to correct are the Gibbs free enthalpies of adsorption of several hydrogen molecules on Pd6. The corrected values are shown in the reproduced Tables 2 and 3. All the corresponding conclusions are still valid.

Table 2 Incremental adsorption energies ΔEads and Gibbs free enthalpies ΔGads in kJ mol−1 for an increasing number of H2 molecules on free Pd6
Number of H2 ΔEads ΔGads
1 −49.2 −24.8
2 −43.8 −9.7
3 −43.7 −20.1
4 −37.8 −10.0
5 −33.7 −9.4
6 −24.2 +6.8
7 −64.8 −22.5


Table 3 Incremental adsorption energies ΔEads and Gibbs free enthalpies ΔGads in kJ mol−1 for an increasing number of H2 molecules on carbon-supported Pd6
Number of H2 ΔEads ΔGads
1 −56.2 −28.5
2 −33.3 −3.2
3 −33.6 −12.0
4 −66.8 −27.7
4s −30.5 +9.7


In contrast to that, the free activation enthalpies for the hydrogen dissociation on Pd6 changed noticeably:

• free Pd6: 40.4 kJ mol−1 (old: 1.4 kJ mol−1)

• carbon-supported cis-configuration: 45.2 kJ mol−1 (old: 3.3 kJ mol−1)

• carbon-supported perpendicular configuration: 22.2 kJ mol−1 (old: 4.1 kJ mol−1)

Therefore, we have to correct our conclusion that hydrogen dissociation on free Pd6 should occur spontaneously at room temperature. ΔG is, at 40.4 kJ mol−1, rather high for this. However, this further confirms our result that it is essential to also study larger cluster sizes (vide infra). Additionally, the conclusion that hydrogen dissociation on carbon-supported Pd6 should occur spontaneously at room temperature is still valid. The free activation barrier for the dissociation is smaller than the Gibbs free enthalpy change for the initial molecular adsorption step.

Also, the values for the Gibbs free enthalpies of dissociation of several hydrogen molecules on Pd6 are affected. However, all the corresponding conclusions are still valid. Tables 4 and 5 are reproduced here and list the corrected values. Further changes are:

Table 4 Incremental dissociation energies ΔEdiss and Gibbs free enthalpies ΔGdiss in kJ mol−1 for an increasing number of H2 molecules on free Pd6
Number of H2 ΔEdiss ΔGdiss
1 −66.7 −36.3
2 −45.7 −15.7
3 −71.5 −42.7
4 −68.8 −32.4


Table 5 Incremental dissociation energies ΔEdiss and Gibbs free enthalpies ΔGdiss in kJ mol−1 for an increasing number of H2 molecules on carbon-supported Pd6
Number of H2 ΔEdiss ΔGdiss
1 −100.0 −72.1
2 −62.8 −33.1
3 −106.1 −71.9


• The third hydrogen molecule has a free dissociation enthalpy 36.7 kJ mol−1 more favourable for the carbon-supported system compared to the free system (old: 18.8 kJ mol−1).

• If one adds one hydrogen atom of the second hydrogen molecule not to the top, but to the unfavourable lower layer of the cluster, the cluster deforms and shows a favourable free dissociation enthalpy of −48.3 kJ mol−1 (old: −18.8 kJ mol−1).

Also, the changes for the Pd21 systems are negligible and all conclusions drawn previously are still valid. The following list reports the changes which occurred due to the correction of the mistake for the Pd21 systems:

• Free activation enthalpy for the hydrogen dissociation on free Pd21: 13.8 kJ mol−1 (old: 2.7 kJ mol−1)

• Free activation enthalpy for the H atom migration from the red configuration: 6.6 kJ mol−1 (old: 10.5 kJ mol−1)

• Free activation enthalpy for the H atom migration from the yellow configuration: 5.0 kJ mol−1 (old: 6.3 kJ mol−1)

The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.

References

  1. L. Warczinski and C. Hättig, Phys. Chem. Chem. Phys., 2019, 21, 21577–21587 RSC.
  2. M. K. Kesharwani, B. Brauer and J. M. L. Martin, J. Phys. Chem. A, 2015, 119, 1701–1714 CrossRef CAS PubMed.

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