Electrodeposition and characterization of cuprous oxide

Rakhshani, A. E.; Al-Jassar, A A; Varghese, Justin Manjaly

doi:10.1016/0040-6090(87)90157-x

Cited by 90 publications

(54 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[13][14][15][16] The crystal orientation of the electrodeposited Cu 2 O is pH dependent; i.e. it is <100> at pH values of 9.0 and 9.5, and <111> at pH values of 12.0 and 12.5.…”

mentioning

confidence: 99%

“…Among thin-film fabrication methods, electrodeposition from an aqueous solution has advantages over conventional methods, such as chemical vapor deposition, because of its low cost and low environmental burden. Moreover, it is easy to obtain cubic Cu 2 O with the preferential <111> orientation by tuning the pH of the electrodeposition bath; [13][14][15][16][17] this orientation relaxes lattice misfit with hexagonal ZnO, which is favorable for Cu 2 O-ZnO solar cells.…”

mentioning

confidence: 99%

“…it is <100> at pH values of 9.0 and 9.5, and <111> at pH values of 12.0 and 12.5. [13][14][15][16][17] The pH dependence of the crystal orientation during Cu 2 O electrodeposition may be ascribable to changes in the dissolved copper(II)-lactate complexes. 6,15,16 Unfortunately, to the best of our knowledge, there are no available thermodynamic data for these copper(II)-lactate complexes under these alkaline conditions, especially for such concentrated solutions.…”

mentioning

confidence: 99%

“…Since the pioneering work of Rakhshani et al, 13 highly concentrated aqueous alkaline solutions have commonly been used for Cu 2 O electrodeposition; [13][14][15][16] these solutions contain 0.4 M of a copper(II) salt and 3.0 M lactic acid (HL; CH 3 CH(OH)COOH) as the complexing agent, and the pH is adjusted to be in the 9.0-12.5 range. [13][14][15][16] The crystal orientation of the electrodeposited Cu 2 O is pH dependent; i.e.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Identification of Copper(II)–Lactate Complexes in Cu₂O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution

Chen

Kitada

Seki

et al. 2018

J. Electrochem. Soc.

View full text Add to dashboard Cite

Unveiling dissolved species in electrodeposition baths helps our understanding of electrodeposition behavior, such as growth orientation. A highly concentrated aqueous alkaline copper(II)-lactate solution is used for the electrodeposition of copper(I) oxide (Cu 2 O) thin films with <111> orientations; the semiconductor properties of these films facilitate their use in solar-cell materials, photocathodes, and photocatalysts. However, the dissolved species, presumably copper(II)-lactate complexes, cannot be deduced on the basis of known thermodynamic data, and have not been convincingly determined yet. In this work, we determine these cupric complexes by pH titration, ultraviolet-visible spectroscopy, and electrospray-ionization mass spectrometry (ESI-MS), including probe-ESI-MS (PESI-MS). Using PESI-MS, we successfully analyzed a highly concentrated solution without sample dilution. The determined complexes are Cu(H -1 L)L -and Cu(H -1 L) 2 2-, where the H -1 L 2-(CH 3 CH(O -)COO -) is a lactate ion with a deprotonated α-hydroxyl group. As far as we know, this is the first direct experimental observation of H -1 L 2-ions in a highly concentrated aqueous alkaline copper(II)-lactate solution. We also propose that H -1 L 2-is stabilized by the high concentration and through coordination to copper(II) ions. Cuprous oxide (Cu 2 O) is a p-type semiconductor that is inexpensive and of low toxicity. Cu 2 O thin films are attracting increasing attention as solar-cell materials, 1-5 photocathodes, 6-9 and photocatalysts 10-12 for, for example, water splitting. Among thin-film fabrication methods, electrodeposition from an aqueous solution has advantages over conventional methods, such as chemical vapor deposition, because of its low cost and low environmental burden. Moreover, it is easy to obtain cubic Cu 2 O with the preferential <111> orientation by tuning the pH of the electrodeposition bath;13-17 this orientation relaxes lattice misfit with hexagonal ZnO, which is favorable for Cu 2 O-ZnO solar cells.Since the pioneering work of Rakhshani et al., 13 highly concentrated aqueous alkaline solutions have commonly been used for Cu 2 O electrodeposition;13-16 these solutions contain 0.4 M of a copper(II) salt and 3.0 M lactic acid (HL; CH 3 CH(OH)COOH) as the complexing agent, and the pH is adjusted to be in the 9.0-12.5 range. [13][14][15][16] The crystal orientation of the electrodeposited Cu 2 O is pH dependent; i.e. it is <100> at pH values of 9.0 and 9.5, and <111> at pH values of 12.0 and 12.5. [13][14][15][16][17] The pH dependence of the crystal orientation during Cu 2 O electrodeposition may be ascribable to changes in the dissolved copper(II)-lactate complexes. 6,15,16 Unfortunately, to the best of our knowledge, there are no available thermodynamic data for these copper(II)-lactate complexes under these alkaline conditions, especially for such concentrated solutions. Two previous reports have indicated the presence of dissolved copper(II)-lactate complexes in such concentrated alkaline solutions; Leopold et al. a...

show abstract

“…[13][14][15][16] The crystal orientation of the electrodeposited Cu 2 O is pH dependent; i.e. it is <100> at pH values of 9.0 and 9.5, and <111> at pH values of 12.0 and 12.5.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Identification of Copper(II)–Lactate Complexes in Cu₂O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution

Chen

Kitada

Seki

et al. 2018

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…KCl)] in a copper sulfate -lactic acid bath. [26][27][28][29][30][31][32] [All potentials in this study are quoted with respect to this reference electrode scale.] The electrolytic bath was prepared with deionized (DI) water and contained 0.4 M copper(II) sulfate (Sigma-Aldrich, 99.9% metals basis) and 3 M lactic acid (Sigma-Aldrich).…”

Section: Methodsmentioning

confidence: 99%

Continuous Flow Photoelectrochemical Reactor for Solar Conversion of Carbon Dioxide to Alcohols

Homayoni

Chanmanee

Dennis

et al. 2015

J. Electrochem. Soc.

View full text Add to dashboard Cite

A newly-designed continuous flow photoelectrochemical reactor (CFPR) was applied to the solar photoelectrosynthesis of alcohols from carbon dioxide (CO 2 ) dissolved in aqueous media. Hybrid p-type CuO/Cu 2 O semiconductor nanorod arrays, prepared by a three-step synthesis method (sol-gel synthesis, thermal anneal, and cathodic electrodeposition) were used as photocathodes. Scanning electron microscopy and powder X-ray diffraction were used to characterize these hybrid materials at various stages of the preparation protocol as well as before and after being subjected to photoelectrolysis for selected periods of time. The performance of the CFPR with the hybrid photocathode was analyzed in CO 2 -saturated aqueous bicarbonate solution at −0.3 V vs Ag/AgCl under simulated AM 1.5 solar irradiation for periods up to 5 h. The hybrid photocathode formulation facilitated efficient photoelectron injection to CO 2 while its robustness and high photoelectrochemically active surface area enhanced the formation of alcohols. Gas chromatographic analyses of the photoelectrolysis solutions under a flow rate of 5 ml/h revealed ethanol to be the main product followed by isopropanol and methanol. The amounts of alcohol assayed indicated a faradaic efficiency ranging from 75 to 96%. The formation of C-C bonds in the products is a significant finding in this study and a mechanistic hypothesis is presented to account for products such as ethanol instead of methanol as is usually seen. Finally, the CFPR performance was numerically simulated to unravel the influence of flow rate and channel geometry on CO 2 conversion and consumption rate. This paper is an extension of recent results on efficient solar photoelectrosynthesis of methanol from carbon dioxide (CO 2 ) using hybrid CuO/Cu 2 O semiconductor nanorod arrays.1,2 Given that CO 2 is the most abundant greenhouse gas, solar photoelectrochemical reduction of CO 2 into an energy form suitable for transportation (such as methanol or other alcohols) is of primary importance for combating atmospheric CO 2 accumulation, and offers a potentially viable strategy for simultaneously responding to the steady growth in fuel demand. [3][4][5] In the late eighties, p-type inorganic semiconductor photoelectrodes such as CdTe and GaP were reported for CO 2 reduction in aqueous solutions.6 Carbon monoxide and formic acid were the main products observed, the first dominating on p-CdTe while the latter was most prevalent on p-GaP. 6 Subsequently, p-GaAs and p-InP were deployed for methanol photogeneration albeit with very high overpotentials. 7More recently, p-GaP and p-FeS 2 photoelectrodes were shown to reduce CO 2 to methanol with the assistance of pyridine or imidazole in the electrolyte as a co-catalyst. 8,9 However, a key drawback with many II-VI and III-V p-type semiconductor materials is that they are either toxic (As, Cd) or not earth-abundant (Te, Ga, In).Aside from II-VI and III-V p-type semiconductors, copper oxides can be considered for CO 2 photoelectroreduction. Copper oxides exist in t...

show abstract

Multi-method Analysis of the Metal/Electrolyte Interface: Scanning Force Microscopy (SFM), Quartz Microbalance Measurements (QMB), Fourier Transform Infrared Spectroscopy (FTIR) and Grazing Incidence X-ray Diffractometry (GIXD) at a Polycrystalline Copper Electrode

Kautek

Geuss

Sahre

et al. 1997

Surf. Interface Anal.

View full text Add to dashboard Cite

The successful application of various in situ and ex situ analytical techniques has been demonstrated at the buried interface between a metal and an electrolyte. Scanning force microscopy (SFM), electrochemical quartz microbalance measurements (EQMB), grazing incidence x‐ray diffractometry (GIXD), Fourier transform infrared spectroscopy (FTIR) in the specular reflection absorption mode and electrochemical charge measurements proved complementary in the characterization of a polycrystalline copper electrode in alkaline 0.1 M sulphate, perchlorate, fluoride and chloride electrolyte contact at pH 12. The surface exhibited a mixture of Cu(111) and Cu(200) grains of the order of 100 nm. Repeated potential scanning in the double layer and passive oxide region, between ‐1.4 and +0.1 VMSE, resulted in a complete reorganization of the surface morphology but no detectable corrosion. The electrochemical exchange of H2O and OH− between the electrolyte and the oxide film took place reversibly in accordance with a solid‐state growth mechanism. The copper atoms were redeposited at crystallographically preferred sites, generating comparatively homogeneously oriented, narrow Cu(111)‐edged grain ridges of length 200 nm. In the Cu(I) potential range, the formation of several monolayers of amorphous Cu2O could be confirmed. Only after extended time periods in the Cu(II) oxide potential region, Cu2O recrystallized to a (111) phase accompanied by Cu2O(200) and Cu2O(110). In this region, one observed the formation of amorphous Cu(OH)2 concurrent with further growth of Cu2O. Strong CuOH IR stretching bands excluded the existence of CuO. At corrosive potentials of +0.25 VMSE, high anodic currents and substantial mass losses led to an electropolished surface with isolated features of <300 nm width and <70 nm height.© 1997 John Wiley & Sons, Ltd.

show abstract

Electrodeposition and characterization of cuprous oxide

Cited by 90 publications

References 13 publications

Identification of Copper(II)–Lactate Complexes in Cu₂O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution

Identification of Copper(II)–Lactate Complexes in Cu₂O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution

Continuous Flow Photoelectrochemical Reactor for Solar Conversion of Carbon Dioxide to Alcohols

Multi-method Analysis of the Metal/Electrolyte Interface: Scanning Force Microscopy (SFM), Quartz Microbalance Measurements (QMB), Fourier Transform Infrared Spectroscopy (FTIR) and Grazing Incidence X-ray Diffractometry (GIXD) at a Polycrystalline Copper Electrode

Contact Info

Product

Resources

About

Electrodeposition and characterization of cuprous oxide

Cited by 90 publications

References 13 publications

Identification of Copper(II)–Lactate Complexes in Cu2O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution

Identification of Copper(II)–Lactate Complexes in Cu2O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution

Continuous Flow Photoelectrochemical Reactor for Solar Conversion of Carbon Dioxide to Alcohols

Multi-method Analysis of the Metal/Electrolyte Interface: Scanning Force Microscopy (SFM), Quartz Microbalance Measurements (QMB), Fourier Transform Infrared Spectroscopy (FTIR) and Grazing Incidence X-ray Diffractometry (GIXD) at a Polycrystalline Copper Electrode

Contact Info

Product

Resources

About

Identification of Copper(II)–Lactate Complexes in Cu₂O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution

Identification of Copper(II)–Lactate Complexes in Cu₂O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution