Electronic Supplementary Material for:
On the effect of Cu on the activity of carbon supported Ni nanoparticles for hydrogen electrode
reactions in alkaline medium
Alexandr G. Oshchepkov,a, b, c Pavel A. Simonov,a, d Olga V. Cherstiouk,a, d Renat R. Nazmutdinov,f
Dmitrii V. Glukhov,f Vladimir I. Zaikovskii,a, d Tatyana Yu. Kardash,a, e Ren I. Kvon,a Antoine
Bonnefont,c Alexandr N. Simonov,g Valentin N. Parmon,a, d Elena R. Savinovab, *
[a] Boreskov Institute of Catalysis, Novosibirsk, 630090, Russia
[b] Institut de Chimie et Procédés pour l'Energie, l'Environnement et la Santé, UMR 7515 CNRSUniversity of Strasbourg, Strasbourg Cedex, 67087, France
[c] Institut de Chimie de Strasbourg, UMR 7177 CNRS- University of Strasbourg, Strasbourg, 67070,
France
[d] Novosibirsk State University, Novosibirsk, 630090, Russia
[e] Research and Educational Center for Energy Efficient Catalysis, Novosibirsk State University,
Novosibirsk, 630090, Russia
[f] Kazan National Research Technological University, Kazan, 420015, Russia
[g] School of Chemistry, Monash University, Clayton, Victoria, 3800, Australia
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SUPPLEMENTARY MATERIALS CONTENT
Fig. S1 showing cyclic voltammograms for the Ni/C, Ni0.50Cu0.50/C catalysts and carbon support Vulcan
XC-72
Fig. S2 showing how the electrocatalytic activity is determined using Ni0.95Cu0.05/C catalyst as an example
Fig. S3 showing TEM image for the Ni0.95Cu0.05/C catalyst with low magnification
Fig. S4 showing TEM images for the Ni90Cu10/C, Ni0.70Cu0.30/C, Ni0.50Cu0.50/C catalysts with elemental
mapping
Experimental details for XP spectra processing
Fig. S5 showing Ni2p and Cu2p XP spectra for the Ni/C, Ni0.95Cu0.05/C, Ni90Cu10/C and Ni0.80Cu0.20/C
catalysts
Experimental details for MC simulations
Table S1 listing parameters of the pair Morse potential
Fig. S6 showing simulated structures obtained at 427 ºC
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Fig. S1 Cyclic voltammograms for the Ni/C (solid), Ni0.50Cu0.50/C (dash) catalysts and the carbon support
Vulcan XC-72 (dot) at 25 ºC in Ar-saturated 0.1 М NaOH solution at a scan rate of 20 mV s-1. Currents
are normalized by the mass of the carbon support
Fig. S2 (a) and (b) demonstrate the quality of fitting of the micropolarisation and of the Tafel potential
interval, respectively, for the Ni0.95Cu0.05/C sample
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Fig. S3 TEM image of the Ni0.95Cu0.05/C catalyst at low magnification
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Fig. S4 HAADF-STEM images of the Ni0.90Cu0.10/C (a), Ni0.70Cu0.30/C (b) and Ni0.50Cu0.50/C (c) catalysts
with elemental mapping of Ni (green) and Cu (red) atoms (a1, b1, c1, correspondingly)
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XP spectra processing
The surface concentrations of the elements (C, O, Ni, and Cu) were calculated from the integrated
intensities of the corresponding photoelectron peaks (see Fig. S5 for Ni2p and Cu2p spectra) using atomic
sensitivity factors tabulated in [1].
For estimating the Ni0 contribution, the Ni2p doublet for the metallic state was fit with 6 components
and subtracted from the experimental XP spectra. It should be noted that XPS data for Ni oxides reported
in the literature make the further spectra deconvolution rather ambiguous. To simplify the curve fitting
procedure only the Ni2p3/2 part of the doublet was treated, and the fitting process was constrained by
assuming that the binding energy of the O1s peak related to Ni2+ oxide is close to 529 eV [2], while O1s
spectra for hydroxyls, carboxyls and coordinated water have values above 530 eV [3]. Targeting the Ni to
O ratio of 1±0.05 for NiO, the contribution of Ni oxides to the Ni2p spectra was fit with two components:
Ni(OH)2 comprising two peaks, and NiO represented by three peaks.
Fig. S5 Ni2p and Cu2p X-Ray photoelectron spectra for the Ni/C (1, black), Ni0.95Cu0.05/C (2, red),
Ni0.90Cu0.10/C (3, blue) and Ni0.80Cu0.20/C (4, gray) catalysts
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Parameters of the Morse potential used in Monte Carlo simulations
Atomic interactions are described by a set pair Morse potentials devised in work [4]:
𝑈 (𝑟ij ) = 𝐷(exp[−2 ∝ (𝑟ij − 𝑟0 )] − 2𝑒𝑥𝑝[−∝ (𝑟ij − 𝑟0 )]),
(1S)
where rij is the distance between i-th and j-th atoms; D is the depth of the potential energy well; r0 is the
position of the potential minimum; and α is a parameter, which characterizes the curvature of the potential
well.
The “non-diagonal” potential parameters for a Ni-Cu alloy were calculated as follows:
(2S)
𝐷Cu−Ni = √𝐷Cu 𝐷Ni
𝑟0Cu−Ni =
𝑟0Cu + 𝑟0Ni
2
(3S)
2∝Cu ∝Ni
Cu + ∝Ni
(4S)
∝Cu−Ni = ∝
Table S1. Parameters of the pair Morse potential
D, eV
r0, Å
α, Å -1
Cu
0.3729 a
2.866
1.3588
Ni
0.4205
2.78
1.4199
a
This value slightly differs from the one reported (0.3429 eV) in the original work [4]; we varied this
parameter in order to reach a better agreement with the experimental atomization energy value.
Fig. S6 Simulated structures for Ni0.20Cu0.80 (a), Ni0.50Cu0.50 (b), Ni0.80Cu0.20 (c) nanoparticles obtained at
427 ºC (Ni – green, Cu – red)
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REFERENCES
1. Moulder JF, Stickle WF, Sobol PE, Bomben KD (1992) Handbook of X Ray Photoelectron
Spectroscopy. Perkin-Elmer Corp., Minnesota, USA
2. Mansour AN (1994) Characterization of NiO by XPS. Surf Sci Spectra 3:231–238.
3. Mansour AN (1994) Characterization of α-Ni(OH)2 by XPS. Surf Sci Spectra 3:255–262.
4. Girifalco LA, Weizer VG (1959) Application of the Morse Potential Function to Cubic Metals. Phys
Rev 114:687–690.
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