Characterization of Electrochemically Prepared <i>γ</i>-NiOOH by XPS

Mansour, A. N.; Melendres, C. A.

doi:10.1116/1.1247756

Cited by 140 publications

(97 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The SEM image shows that the solid consists of aggregates of submicron particles (Figure 4 b). In the X-ray photoelectron spectrum (XPS) of the particles a Ni 2p 3/2 peak appears at 855.5 eV (Figure 5 A), which is similar to typical values observed for nickel oxyhydroxide (b-NiOOH: 855.5 eV; [57] g-NiOOH: 855.3 eV [58] ). In the X-ray photoelectron spectrum (XPS) of the particles a Ni 2p 3/2 peak appears at 855.5 eV (Figure 5 A), which is similar to typical values observed for nickel oxyhydroxide (b-NiOOH: 855.5 eV; [57] g-NiOOH: 855.3 eV [58] ).…”

Section: Detection and Isolation Of Particles Formed During Water Oxisupporting

confidence: 77%

Efficient Chemical and Visible‐Light‐Driven Water Oxidation using Nickel Complexes and Salts as Precatalysts

Chen

et al. 2013

ChemSusChem

View full text Add to dashboard Cite

Chemical and visible-light-driven water oxidation catalyzed by a number of Ni complexes and salts have been investigated at pH 7-9 in borate buffer. For chemical oxidation, [Ru(bpy)3](3+) (bpy = 2,2'-bipyridine) was used as the oxidant, with turnover numbers (TONs) >65 and a maximum turnover frequency (TOFmax) >0.9 s(-1). Notably, simple Ni salts such as Ni(NO3 )2 are more active than Ni complexes that bear multidentate N-donor ligands. The Ni complexes and salts are also active catalysts for visible-light-driven water oxidation that uses [Ru(bpy)3](2+) as the photosensitizer and S2 O8 (2-) as the sacrificial oxidant; a TON>1200 was obtained at pH 8.5 by using Ni(NO3)2 as the catalyst. Dynamic light scattering measurements revealed the formation of nanoparticles in chemical and visible-light-driven water oxidation by the Ni catalysts. These nanoparticles aggregated during water oxidation to form submicron particles that were isolated and shown to be partially reduced β-NiOOH by various techniques, which include SEM, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, XRD, and IR spectroscopy. These results suggest that the Ni complexes and salts act as precatalysts that decompose under oxidative conditions to form an active nickel oxide catalyst. The nature of this active oxide catalyst is discussed.

show abstract

Section: Detection and Isolation Of Particles Formed During Water Oxisupporting

confidence: 77%

Efficient Chemical and Visible‐Light‐Driven Water Oxidation using Nickel Complexes and Salts as Precatalysts

Chen

et al. 2013

ChemSusChem

View full text Add to dashboard Cite

show abstract

“…Binding energy values for the O 1s XPS peak of NiO have been reported in the range of 529.6 and 529.8 eV (Table 2). Mansour and Melendres (1996a) provide XPS spectra for Ni 2 O 3 ·6H 2 O. The O 1s spectrum reveals contributions at binding energy values of 529.3 eV (attributed to Ni 2 O 3 ), 530.8 eV [attributed to Ni(OH) 2 ], and 532.3 eV (attributed to water).…”

Section: Discussionmentioning

confidence: 99%

X-ray photoelectron spectroscopic study of a pristine millerite (NiS) surface and the effect of air and water oxidation

Legrand

Nesbitt

Bancroft

1998

American Mineralogist

156

View full text Add to dashboard Cite

Millerite, NiS, fractured under high vacuum and reacted with air and water has been analyzed by X-ray photoelectron spectroscopy (XPS). The pristine millerite surface gives rise to photoelectron peaks at binding energies of 853.1 eV (Ni ) and 161.7 eV (S 2p 3/2 2p), thus resolving ambiguities concerning binding energies quoted in the literature. Airreacted samples show the presence of NiSO 4 and Ni(OH) 2 species. There is evidence for polysulfide species (S , where 2 Յ n Յ 8) on air-oxidized surfaces. These may occur in 2Ϫ n a sub-surface layer or may be intermixed with the Ni(OH) 2 in the oxidized layer. The NiSO 4 species at the millerite surface occur as discrete crystallites whereas the Ni(OH) 2 forms a thin veneer covering the entire millerite surface. The NiSO 4 crystallites form on the surface of millerite but not on surfaces of adjacent minerals. Surface diffusion of Ni 2ϩ and SO across the millerite surface is thought to be responsible for the transport and 2Ϫ 4 subsequent growth of NiSO 4 crystallites developed on millerite surfaces. Although it is clear that Ni and SO does not diffuse onto surfaces of adjacent minerals in sufficient 2Ϫ 4quantity to form crystallites, the explanation is uncertain. XPS results for water-reacted surfaces show little difference from the vacuum fractured surfaces with the exception that minor amounts of polysulfide and hydroxy nickel species are present. Similar reaction products to those formed in air [NiSO 4 and Ni(OH) 2 ] are believed to be produced, but these are removed from the millerite surface by dissolution, leaving behind a sulfur-enriched surface (polysulfide) and hydroxyl groups chemisorbed to nickel ions at the millerite surface.

show abstract

“…In the hydroxide-containing phases Ni͑OH͒ 2 and NiOOH, the situation is not so clear and peak values between ϳ530.5 and ϳ531.7 eV have been obtained. 42,45,[47][48][49] Furthermore, NiOOH can hardly be distin- guished from hydrated forms of Ni 2 O 3 . 49,50 The O 1s peak emanating from adsorbed H 2 O or OH − groups is centered at ϳ532.7 eV.…”

Section: Pes Datamentioning

confidence: 99%

Coloration Mechanism in Proton-Intercalated Electrochromic Hydrated NiO[sub y] and Ni[sub 1−x]V[sub x]O[sub y] Thin Films

Avendaño¹,

Rensmo

Azens

et al. 2009

J. Electrochem. Soc.

View full text Add to dashboard Cite

Electrochromic ͑EC͒ films of nickel oxide, with and without vanadium, were prepared by reactive dc magnetron sputtering. They were characterized by electrochemical and optical measurements and studied by X-ray photoelectron spectroscopy ͑PES͒ using synchrotron radiation. The films were analyzed under as-deposited conditions and after bleaching/coloration by insertion/ extraction of protons from a basic solution and ensuing charge stabilization. Optical measurements were consistent with a coloration process due to charge-transfer transitions from Ni 2+ to Ni 3+ states. The PES measurements showed a higher concentration of Ni 3+ in the colored films. Moreover, two peaks were present in the O 1s spectra of the bleached film and pointed to contributions of Ni͑OH͒ 2 and NiO. The changes in the O 1s spectra upon coloration treatment indicate the presence of Ni 2 O 3 in the colored film and necessitated an extension of the conventional model for the mechanism of EC coloration. The model involves not only proton extraction from nickel hydroxide to form nickel oxyhydroxide but also participation of NiO in the coloration process to form Electrochromic ͑EC͒ materials are able to change their optical properties reversibly and persistently upon charge insertion/ extraction under the application of an external voltage.1 Materials that color upon charge insertion/extraction are called cathodic/ anodic. These materials can be implemented in energy-saving and comfort-enhancing architectural "smart windows," and other application areas include mirrors with variable specular reflectance, nonemissive information displays, surfaces with variable thermal emittance, eyewear, etc.1-4 EC technology has been used for some niche applications for several years. However, the situation is now changing and electrochromism will reach wider applications. 5Thin films of Ni oxide possess anodic electrochromism, as discovered in the mid-1980s 6-9 and subsequently studied in a large number of investigations. [1][2][3][4] The visual appearance goes between transparent and brown upon extraction and insertion of charge. In EC devices incorporating cathodically coloring W oxide films, the brown color of Ni oxide is complementary to the blue color of W oxide, both together yielding a neutral ͑gray͒ color in transmittance for dark films. Ni oxide films produced for EC applications exhibit a cubic polycrystalline structure 1,9-14 and a density between 3 and 6.5 g/cm 3 depending on deposition conditions. 1,14,15 The low density is indicative of porosity. 10,14,16 The grain size depends strongly on film deposition conditions and can range from 3 to 300 nm. 9,10,12,14,15,17 The porosity and small grain size, leading to a large surface-to-bulk ratio, increase the EC activity of the films, 12,18,19 and the reaction that produces the color takes place in the outermost parts of the grains. 12Several varieties of reactively sputter-deposited EC hydrated nickel-based oxide thin films have been reported. [1][2][3][4]20 Optimized Ni 1−x V x O y films made by sputter...

show abstract

Characterization of Electrochemically Prepared γ-NiOOH by XPS

Cited by 140 publications

References 6 publications

Efficient Chemical and Visible‐Light‐Driven Water Oxidation using Nickel Complexes and Salts as Precatalysts

Efficient Chemical and Visible‐Light‐Driven Water Oxidation using Nickel Complexes and Salts as Precatalysts

X-ray photoelectron spectroscopic study of a pristine millerite (NiS) surface and the effect of air and water oxidation

Coloration Mechanism in Proton-Intercalated Electrochromic Hydrated NiO[sub y] and Ni[sub 1−x]V[sub x]O[sub y] Thin Films

Contact Info

Product

Resources

About