Estimation of delafossite p-type CuGaO2/ZnO hybrids as semiconductor photocatalyst by controlling particle size

Choi, Minuk; Yagi, Sota; Ohta, Yasuhiro; Kido, Kenji; Hayakawa, Tomokatsu

doi:10.1016/j.jpcs.2020.109845

Cited by 11 publications

(11 citation statements)

References 29 publications

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“…In our previous study, we found that CZ4 had better photocatalytic properties because the larger CuGaO 2 hexagonal plates were well-coated with ZnO. [42]AZnO layer of su cient thickness is expected to extract electrons from electron-hole pairs generated at the p-n interface between CuGaO 2 and ZnO and prevent electrons from returning to the interface with p-type CuGaO 2 , resulting in the higher photocatalytic performance demonstrated in our previous study.…”

Section: Micro-raman Investigationmentioning

confidence: 83%

“…A comprehensive discussion related to the SEM-EDS investigation of CuGaO 2 /ZnO hybrids was also provided in a previous work. [42] In the last part of this session, we shall discuss on the formation mechanism of ZnCu 2 O 4 and CuGa 2 O 4 .…”

Section: Resultsmentioning

confidence: 99%

“…Compared with CGO2, CGO1has a smaller size, indicating that it has a higher speci c surface area. [42] Therefore, more oxygen molecules are likely to be adsorbed on CGO1 and more dominantly triggerthe decompositionreaction. For CZ3 when [Zn]/[Cu] ratio=11 and CGO1 is used, CuO and Ga…”

Section: Resultsmentioning

confidence: 99%

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Micro-Raman and X-ray Photoemission Spectroscopic Investigations of Heterojunction Between Delafossite CuGaO2 and Wurtzite ZnO Obtained by Hydrothermal Method

Choi

Brabec

Hayakawa

2022

Preprint

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P-type delafossite CuGaO2 is a wide-bandgap semiconductor for optoelectronic applications, and its lattice parameters are very similar to those of n-type semiconductor wurtzite ZnO. Therefore, the investigation on p-n junction properties of crystalline CuGaO2 /ZnO heterostructures has attracted significant attention. In this study, interfacial CuGaO2 /ZnO heterojunctions were examined through X-ray diffraction (XRD) analysis, confocal micro-Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). XRD analysis revealed that the hydrothermal deposition of ZnO on hexagonal platelet CuGaO2 base crystals was successful, and the subsequent reduction process could induce a unique reaction between CuGaO2 and ZnO. XPS allowed the comparison of the binding energies (peak position and width) of the valence electrons of the constituents (Cu, Ga, (Zn) and O) of the pristine CuGaO2 single crystallites and of crystalline CuGaO2 /ZnO heterojunctions. The presence of distorted GaO6 octahedra at the CuGaO2 /ZnO hybrid interface and the absence of Cu2+ ions were the main characteristics of the chemically well-reconstructed heterojunction interface that facilitated effective carrier separation.

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Section: Micro-raman Investigationmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 99%

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Micro-Raman and X-ray Photoemission Spectroscopic Investigations of Heterojunction Between Delafossite CuGaO2 and Wurtzite ZnO Obtained by Hydrothermal Method

Choi

Brabec

Hayakawa

2022

Preprint

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“…In contrast to lots of work focusing on the application of p-type ABO 2 oxides in water electrolysis, very few studies have paid attention to CuGaO 2 (CGO) oxides. CGO is of great potential in catalytic materials because of its ultra-high carrier mobility, appropriate bandgap (~ 2.0 eV), and excellent long-term stability [26][27][28]. Ahmed and Mao [29] prepared three different morphologies of CGO, namely nanoparticles, submicron hexagons, and micron-sized particles, by a hydrothermal method at 190 °C, a sono-chemical method at 850 °C, and a solid-state reaction at 1150 °C, respectively.…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal synthesized delafossite CuGaO2 as an electrocatalyst for water oxidation

Gao

Yang

Liu

et al. 2022

Front. Optoelectron.

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Hydrogen production from water splitting provides an effective method to alleviate the ever-growing global energy crisis. In this work, delafossite CuGaO2 (CGO) crystal was synthesized through hydrothermal routes with Cu(NO3)2·3H2O and Ga(NO3)3·xH2O used as reactants. The addition of cetyltrimethylammonium bromide (CTAB) was found to play an important role in modifying the morphology of CuGaO2 (CGO-CTAB). With the addition of CTAB, the morphology of CGO-CTAB samples changed from irregular flake to typical hexagonal sheet microstructure, with an average size of 1–2 μm and a thickness of around 100 nm. Furthermore, the electrocatalytic activity of CGO-CTAB crystals for oxygen evolution reaction (OER) was also studied and compared with that of CGO crystals. CGO-CTAB samples exhibited better activity than CGO. An overpotential of 391.5 mV was shown to be able to generate a current density of 10 mA/cm2. The as-prepared samples also demonstrate good stability for water oxidation and relatively fast OER kinetics with a Tafel slope of 56.4 mV/dec. This work highlights the significant role of modification of CTAB surfactants in preparing CGO related crystals, and the introduction of CTAB was found to help to improve their electrocatalytic activity for OER. Graphical abstract

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“…Among them, delafossite oxides possess unique layered nanostructure of ABO 2 , [29] where A = Cu + or Ag + , B = Al 3 + , Ga 3 + , Co 3 + , Cr 3 + , Fe 3 + , etc. Previous studies demonstrated that delafossite oxides like CuAlO 2 , [30][31][32][33][34] CuCoO 2 , [35,36] CuFeO 2 , [37][38][39] CuGaO 2 [27,40,41] and CuCrO 2 [26,[42][43][44][45] can exhibit flexible chemistry and favorable stability, [46] enabling the promotion of electrocatalytic reactions. [47] As a result, researches about delafossite oxides towards electrocatalytic reactions such as oxygen reduction reaction, [48] oxygen evolution reaction [47,49] and hydrogen evolution reaction [47] have attracted extensive research interest.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Methanol Electrooxidation Performance Based on Pt Cluster‐Decorated CuCoO₂ on Carbon

et al. 2022

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Nowadays, the high cost and poor durability of commercial catalyst Pt/C for methanol oxidation reaction have impeded the further development of direct methanol fuel cells. Herein, we firstly introduced a delafossite CuCoO2 to act as the support of noble metal Pt. The strong metal support interaction between Pt and CuCoO2, abundant hydroxide species and active sites on the surface of catalyst may be the key factors for enhanced performances of methanol oxidation. Pt‐CuCoO2/C achieved a mass activity of 1.16 A mgPt−1, which obtained 3.02 times enhancement compared with commercial Pt/C (0.38 A mgPt−1). The If/Ib value of Pt‐CuCoO2/C is 1.96, much higher than that of Pt/C (0.76), demonstrating favorable anti‐poisoning ability. After 200 times cycling, Pt‐CuCoO2/C still maintained 77.1 % of its initial activity, exhibiting superior COads intermediate tolerance and stability. Low cost, better performances and stability of Pt‐CuCoO2/C reveal that it can be seen as a hopeful catalyst.

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Estimation of delafossite p-type CuGaO2/ZnO hybrids as semiconductor photocatalyst by controlling particle size

Cited by 11 publications

References 29 publications

Micro-Raman and X-ray Photoemission Spectroscopic Investigations of Heterojunction Between Delafossite CuGaO2 and Wurtzite ZnO Obtained by Hydrothermal Method

Micro-Raman and X-ray Photoemission Spectroscopic Investigations of Heterojunction Between Delafossite CuGaO2 and Wurtzite ZnO Obtained by Hydrothermal Method

Hydrothermal synthesized delafossite CuGaO2 as an electrocatalyst for water oxidation

Enhanced Methanol Electrooxidation Performance Based on Pt Cluster‐Decorated CuCoO₂ on Carbon

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Estimation of delafossite p-type CuGaO2/ZnO hybrids as semiconductor photocatalyst by controlling particle size

Cited by 11 publications

References 29 publications

Micro-Raman and X-ray Photoemission Spectroscopic Investigations of Heterojunction Between Delafossite CuGaO2 and Wurtzite ZnO Obtained by Hydrothermal Method

Micro-Raman and X-ray Photoemission Spectroscopic Investigations of Heterojunction Between Delafossite CuGaO2 and Wurtzite ZnO Obtained by Hydrothermal Method

Hydrothermal synthesized delafossite CuGaO2 as an electrocatalyst for water oxidation

Enhanced Methanol Electrooxidation Performance Based on Pt Cluster‐Decorated CuCoO2 on Carbon

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Product

Resources

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Enhanced Methanol Electrooxidation Performance Based on Pt Cluster‐Decorated CuCoO₂ on Carbon