Diagnostic spectra for XPS analysis of CuOSH compounds

Chawla, S. K.; Sankarraman, N.; Payer, Joe H.

doi:10.1016/0368-2048(92)80047-c

Cited by 228 publications

(180 citation statements)

References 13 publications

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“…The literature reports metallic Cu with a characteristic peak in the range of 918.2 to 918.6 eV; Cu 2 O has a reported peak between 916.0 and 916.4 eV, and the peak for the CuO standard increases from 917.6 to 917.8 eV. [49][50][51][52][53][54][55] The acid-treated Cu sheet resulted in spectra similar to those previously reported in the literature for air-oxidized metallic Cu. 54,55 This oxidized layer was reported to be in the size range of 1.6 to 2.7 nm.…”

Section: Structural Characterizationsupporting

confidence: 77%

“…The XPS spectra of the Cu 2p region are very challenging to interpret because the metallic state of Cu and Cu(I) have statistically similar binding energy values ( Figure S7a). [49][50][51][52][53][54][55] Hence, the X-ray generated Auger spectra were recorded in the Cu L 3 M 45 M 45 region, and the results are presented in Figure 7a. The literature reports metallic Cu with a characteristic peak in the range of 918.2 to 918.6 eV; Cu 2 O has a reported peak between 916.0 and 916.4 eV, and the peak for the CuO standard increases from 917.6 to 917.8 eV.…”

Section: Structural Characterizationmentioning

confidence: 99%

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Cu–Sn Bimetallic Catalyst for Selective Aqueous Electroreduction of CO₂ to CO

et al. 2016

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ABSTRACT. We report a selective and stable electrocatalyst utilizing non-noble metals consisting of Cu and Sn for the efficient and selective reduction of CO 2 to CO over a wide potential range. The bimetallic electrode was prepared through the electrodeposition of Sn species on the surface of oxide-derived copper (OD-Cu). The Cu surface, when decorated with an optimal amount of Sn, resulted in a Faradaic efficiency (FE) for CO greater than 90% and a current density of −1.0 mA cm −2 at −0.6 V vs. RHE, compared to the CO FE of 63% and −2.1 mA cm −2 for OD-Cu. Excess Sn on the surface caused H 2 evolution with a decreased current density. X-ray diffraction (XRD) suggests the formation of Cu-Sn alloy. Auger electron spectroscopy of the sample surface exhibits zero-valent Cu and Sn after the electrodeposition step. Density functional theory (DFT) calculations show that replacing a single Cu atom with a Sn atom leaves the d-band orbitals mostly unperturbed, signifying no dramatic shifts in the bulk electronic structure. However, the Sn atom discomposes the multi-fold sites on pure Cu, Page 1 of 37 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 2 disfavoring the adsorption of H and leaving the adsorption of CO relatively unperturbed. Our catalytic results along with DFT calculations indicate that the presence of Sn on reduced OD-Cu diminishes the hydrogenation capability-i.e., the selectivity towards H 2 and HCOOH-while hardly affecting the CO productivity. While the pristine monometallic surfaces (both Cu and Sn) fail to selectively reduce CO 2 , the Cu-Sn bimetallic electrocatalyst generates a surface that inhibits adsorbed H*, resulting in improved CO FE. This study presents a strategy to provide a low-cost non-noble metals that can be utilized as a highly selective electrocatalyst for the efficient aqueous reduction of CO 2 . ACS Paragon Plus Environment ACS Catalysis

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Section: Structural Characterizationsupporting

confidence: 77%

Section: Structural Characterizationmentioning

confidence: 99%

Cu–Sn Bimetallic Catalyst for Selective Aqueous Electroreduction of CO₂ to CO

et al. 2016

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“…29 The more definitive signature is an intense satellite (at 940-945 eV) above the 2p 3/2 core-line peak that is characteristic for Cu 2+ but not Cu 1+ or Cu 0 (Two theories involving either a "shake-up" or a "shake-down" process have been proposed; both predict that the satellite is only possible for Cu 2+ where empty 3d conduction states are available). 30,31 The absence of such a satellite and the resemblance of the spectra to those of copper (I) …”

Section: A Xpsmentioning

confidence: 99%

Thermoelectric properties ofp-type CuInSe2chalcopyrites enhanced by introduction of manganese

et al. 2011

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Thermoelectric properties, X-ray photoelectron spectroscopy, Raman spectroscopy, and electronic structures have been studied for Mn-substituted CuInSe 2 chalcopyrites. Raman spectroscopy verifies the lattice disorder due to the introduction of Mn into the CuInSe 2 matrix, leading to a slight suppression of thermal conductivity. On the other hand, the Mn substitution significantly increases the electrical conductivity and Seebeck coefficient. Therefore the thermoelectric figure of merit, ZT, has been enhanced by over two orders of magnitude by the introduction of Mn into CuInSe 2 . These materials are p-type degenerate semiconductors, containing divalent Mn species as confirmed by X-ray photoelectron spectroscopy. The crystal structure of Mn-substituted CuInSe 2 , as well as related ternary and quaternary diamond-like semiconductors, can be viewed as a combination of an electrically conducting unit, the

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“…To gain a better insight to the oxidation state of the central metal atom, we decided to carry out an X-ray photoelectron spectroscopy (XPS) analysis of selected complexes. XPS analysis, in fact, is helpful in identifying the oxidation states of elements in various compounds because the binding energy (BE) measured for the core electrons undergoes a "chemical shift" as a result of changes in the chemical environment of the atoms [49]. The Cu2p spin-orbit doublets (2p 1/2 and 2p 3/2 ) obtained from complex 12 are illustrated in Fig.…”

mentioning

confidence: 99%

“…The fact that small peaks due to the presence of some Cu (II) are present suggests that the surface of the particles was easily oxidized. We must underline that XPS analysis is a surface technique and that a partial oxidation of the surface may always occur [49].…”

mentioning

confidence: 99%