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<p>Theoretical DTF calculations are performed to evaluate the reactivity of Ni–Cu(100) and Ru–Cu(100) bimetallic surfaces towards methane and its fragments adsorption and activation. Possible and preferred adsorption sites for CH<sub>4</sub>, CH<sub>3</sub>, CH<sub>2</sub>, CH, C and H species at 0.25 coverage are presented in this work. Corresponding adsorption energies for all the available surface sites for each species have been determined. Structural parameters for all adsorbed species are also given. From this work, therefore, it can be said that the interaction strengths between methane as well as its fragments and the Ru–Cu(100) surface are the strongest. Compared to Ni–Cu(100), the ruthenium-copper based catalyst stabilizes the methane and its fragments more effectively. In this process, ruthenium’s 4d band center is located at higher energy and the density of states near Fermi level is higher compared to the Ni 3d&#xa0;band. Bimetallic Ru–Cu(100) surface is more active and therefore present a good catalyst for methane and its fragments activations. In addition, the activation energies for CH<sub>4</sub> complete dehydrogenation on Ru–Cu(100) are reproduced. The calculations reveal that the activation of CH<sub>2</sub> into CH and H is kinetically slow, indicating that methylene dissociation is a rate-limiting step. The results suggest that Ru alloying improves the Cu(100) catalytic proprieties for methane decomposition by helping to reduce the coking and promoting the hydrogen production.</p>

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Theoretical study of dissociative adsorption of CH4 fragments on Ru–Cu(100) and Ni–Cu(100) surfaces

  • 期刊论文

  • 发表日期：

    2026年4月18日

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  • Somia Benchikh,
  • Habib Khettal,
  • Mohamed Fahim Haroun,
  • Hiba Khatir,
  • Kamel Kassali,
  • Mebarek Boukelkoul

摘要

Theoretical DTF calculations are performed to evaluate the reactivity of Ni–Cu(100) and Ru–Cu(100) bimetallic surfaces towards methane and its fragments adsorption and activation. Possible and preferred adsorption sites for CH4, CH3, CH2, CH, C and H species at 0.25 coverage are presented in this work. Corresponding adsorption energies for all the available surface sites for each species have been determined. Structural parameters for all adsorbed species are also given. From this work, therefore, it can be said that the interaction strengths between methane as well as its fragments and the Ru–Cu(100) surface are the strongest. Compared to Ni–Cu(100), the ruthenium-copper based catalyst stabilizes the methane and its fragments more effectively. In this process, ruthenium’s 4d band center is located at higher energy and the density of states near Fermi level is higher compared to the Ni 3d band. Bimetallic Ru–Cu(100) surface is more active and therefore present a good catalyst for methane and its fragments activations. In addition, the activation energies for CH4 complete dehydrogenation on Ru–Cu(100) are reproduced. The calculations reveal that the activation of CH2 into CH and H is kinetically slow, indicating that methylene dissociation is a rate-limiting step. The results suggest that Ru alloying improves the Cu(100) catalytic proprieties for methane decomposition by helping to reduce the coking and promoting the hydrogen production.