Hydrogen Evolution on Single‐Crystal Copper and Silver: A Theoretical Study

Santos, Elizabeth; Pötting, K.; Lundin, Angelica; Quaino, Paola; Schmickler, Wolfgang

doi:10.1002/cphc.200900808

Cited by 25 publications

(23 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In both cases, the rate is somewhat faster on the (111) than on the (100) surfaces [15,18–19], and the adsorption energy is also lower on the more compact surfaces [20]. Theses differences are so small that we could not show them in our plot, but they are well established.…”

Section: Discussionmentioning

confidence: 91%

Volcano plots in hydrogen electrocatalysis – uses and abuses

Quaino¹,

Juárez²,

Santos³

et al. 2014

Beilstein J. Nanotechnol.

Self Cite

475

415

View full text Add to dashboard Cite

SummarySabatier’s principle suggests, that for hydrogen evolution a plot of the rate constant versus the hydrogen adsorption energy should result in a volcano, and several such plots have been presented in the literature. A thorough examination of the data shows, that there is no volcano once the oxide-covered metals are left out. We examine the factors that govern the reaction rate in the light of our own theory and conclude, that Sabatier’s principle is only one of several factors that determine the rate. With the exception of nickel and cobalt, the reaction rate does not decrease for highly exothermic hydrogen adsorption as predicted, because the reaction passes through more suitable intermediate states. The case of nickel is given special attention; since it is a 3d metal, its orbitals are compact and the overlap with hydrogen is too low to make it a good catalyst.

show abstract

Section: Discussionmentioning

confidence: 91%

Volcano plots in hydrogen electrocatalysis – uses and abuses

Quaino¹,

Juárez²,

Santos³

et al. 2014

Beilstein J. Nanotechnol.

Self Cite

475

415

View full text Add to dashboard Cite

show abstract

“…A theoretical study using Marcus-type modeling for the Cu(111) surface has yielded an activation Gibbs energy of 0.71 eV for H 2 evolution and for the (100) surface a larger value of 0.79 eV was calculated. 29 In Ref. 8 the activation energy for evolution from a polycrystalline Cu surface at pH = 8 and p(H 2 ) = 1 atm was estimated from measured exchange current densities to be 0.32 eV, and this value should be appropriate for the analysis made here.…”

Section: Electochemical Deposition Of H(ads) On Cu(111) and H 2 Evolumentioning

confidence: 99%

Theory of Hydrogen Deposition and Evolution on Cu(111) Electrodes

Zhao¹,

Anderson²

2017

J. Electrochem. Soc.

View full text Add to dashboard Cite

The amount of under-potential-deposited (UPD) H(ads), if it forms on Cu(111), is small compared to what forms on Pt(111). According to experimental literature, current density on polycrystalline copper increases slowly in the over-potential-deposited (OPD) potential range beginning at 0 V and rises rapidly at several hundred mV negative potential. Using a comprehensive density functional theory for the electrochemical interface, including Fermi level shifts, in this article we attribute this behavior to calculated weak H adsorption which requires the potential to be reduced to ∼0.0 V(SHE) in order for H(ads) deposition to commence. A literature estimate, based on exchange current densities, of the activation energy for H 2 evolution at 0 V is ∼0.32 eV. As the coverage increases with increasingly negative potentials, we calculate the H adsorption energy decreases at a rate 0.27 eV/V for Cu(111), and this will decrease the effective activation energy. We propose that the observed rapid increase in current density at approximately −0.4 V corresponds to ∼0.5 ML coverage by H(ads) and reflects the decreasing activation energy at more negative potentials. We also relate our calculated findings to the literature for electroless copper deposition and to literature for palladium-doped copper as a heterogeneous hydrogenation catalyst. In this article we used quantum theory to explore hydrogen evolution from Cu(111) electrode surfaces. Hydrogen atoms bond weakly to copper surfaces and for significant hydrogen evolution to take place, an overpotential relative to the 0.0 V standard reversible potential must be applied. The first step is deposition of H(ads). In acidic electrolyte the reaction isand in alkaline electrolyteThere are additional ways in which hydrogen can be introduced to copper surfaces as H(ads). In alkaline electrolytes hydrogen is evolved from copper surfaces when aldehyde groups are oxidized without potential control in alkaline electrolyte, that is at the potentials of zero charge (PZC), during electroless copper deposition. [1][2][3][4] In this case the goal is depositing copper atoms on selected substrates and H 2 , formed from combination of H(ads) on copper, 4 is a secondary product. Hydrogen can also be introduced to copper surfaces as H(ads) by spillover of H bonded to Pd atoms on the copper surface. [5][6][7] In this case H 2 dissociation is activated by the Pd ad-atom and the weakly held spilled-over H(ads) performs hydrogenation of organic molecules.To reduce water to hydrogen in alkaline electrolytes over copper electrodes requires high overpotentials of around 0.2 V. 8,9 This contrasts with the small overpotential over platinum. Exchange current densities for hydrogen evolution in alkaline electrolyte for several transition metals, including copper, have been correlated to theoretically calculated H 2 (g) chemisorption energies in a volcano plot. 9 In the plot Pt is near the peak on the left hand side and Pd, Fe, Ni, Co, and W were also on the left (too strongly adsorbed) and Cu, Au, and Ag wer...

show abstract

“…The differences in the rate constants between various facets of Ag and Cu are not large and, as yet, unexplained. Hence, we have also investigated the hydrogen evolution on silver and copper on open crystal faces, such as (100) surfaces, and compared our results with the (111) surfaces [17].…”

Section: Hydrogen Reaction On Single-crystal Surfacesmentioning

confidence: 99%

Recent Progress in Hydrogen Electrocatalysis

Quaino

Santos

Soldano

et al. 2011

Advances in Physical Chemistry

View full text Add to dashboard Cite

Recently, we have proposed a unified model for electrochemical electron transfer reactions which explicitly accounts for the electronic structure of the electrode. It provides a framework describing the whole course of bond-breaking electron transfer, which explains catalytic effects caused by the presence of surface d bands. In application on real systems, the parameters of this model—interaction strengths, densities of states, and energies of reorganization—are obtained from density functional theory (DFT). In this opportunity, we review our main achievements in applying the theory of electrocatalysis. Particularly, we have focused on the electrochemical adsorption of a proton from the solution—the Volmer reaction—on a variety of systems of technological interest, such as bare single crystals and nanostructured surfaces. We discuss in detail the interaction of the surface metal d band with the valence orbital of the reactant and its effect on the catalytic activity as well as other aspects that influence the surface-electrode reactivity such as strain and chemical factors.

show abstract

Hydrogen Evolution on Single‐Crystal Copper and Silver: A Theoretical Study

Cited by 25 publications

References 39 publications

Volcano plots in hydrogen electrocatalysis – uses and abuses

Volcano plots in hydrogen electrocatalysis – uses and abuses

Theory of Hydrogen Deposition and Evolution on Cu(111) Electrodes

Recent Progress in Hydrogen Electrocatalysis

Contact Info

Product

Resources

About