Branched CdO/ZnO Core/Shell Heterogeneous Structure and Its Enhanced Photoelectrocatalytic Performance

Sun, Pu; Liu, Ruping; Ma, Ruifang; Xie, Zhengdao; Su, Fan; Gong, Yanfang; Mu, Zeming; Li, Luhai; Wei, Yen; Wan, Qiang

doi:10.1021/acsomega.8b00457

Cited by 17 publications

(7 citation statements)

References 43 publications

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“…As expected, the absorption peaks are not stronger in this region, suggesting its origin from the characteristic direct and indirect transitions of CdO. 52 Furthermore, the band gap values are obtained as the intercepts on the x-axis by extrapolating the linear part of the Tauc plots of (αhν) 2 CdO_2c; 2.00−1.84 eV for CdO_3a−CdO_3c) corroborate well with the literature. 53 The concept of quantum confinement is applicable here, which correlates the band gap value with the particle size�as the particle size increases, the band gap value decreases.…”

Section: ■ Experimental Sectionsupporting

confidence: 88%

CdO Nanostructures as Acid–Base Bifunctional Heterogeneous Catalysts for Making Coumarin-3-carboxylic Acids at Room Temperature

Kaur,

Mandal

2024

ACS Appl. Nano Mater.

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In this work, cadmium oxide (CdO) nanostructures were fabricated in good yields by calcining three different cadmium-based coordination polymer (CP) precursors, with a change in the alkyl group (methyl, ethyl, and tert-butyl) on the tridentate capping ligand, at 600 °C. The precursor-independent spherical morphology was observed in all the cases. On the other hand, a temperature-dependent hierarchical evolution of morphology from spherical (at 600 °C) to octahedron (at 700 °C) to icosahedron (at 800 °C) was observed for each of the precursors, as investigated by field-emission scanning electron microscopy. This hierarchical change in morphology has further been confirmed by the transmission electron microscopy (TEM) analysis. For all three CPs, the increase in the particle size of the nanostructures was correlated to an increase in the calcination temperature. With the help of Raman spectroscopy, the vibrational modes in these nanostructures were depicted, where the transversal and optical phonon modes and second-order optical modes displayed peaks at 270 and 950 cm −1 , respectively. The energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy (XPS) were utilized for determining the elemental composition of the nanostructures�the presence of Cd and O only�evidencing their purity. The XPS analysis has also confirmed the Cd 2+ and O 2− oxidation states with the appearance of peaks in the ranges of 403−411 eV and 520−532 eV, respectively. Furthermore, the powder X-ray diffraction revealed the cubic phase of all the nanostructures. This was reaffirmed by the high-resolution transmission electron microscopy. Their characteristic absorption features were examined by the solid-state UV−vis diffuse reflectance spectroscopy, which showed a shoulder peak between 490 and 550 nm, and the resultant Tauc plots provided the band gap values in the range of 1.74−2 eV. A relationship of band gap values with particle sizes was established to justify the presence of the quantum confinement effect. Exploring their acid−base bifunctional nature, the spherical nanostructure (obtained at 600 °C) with the highest band gap value emerges as an extremely efficient, and recyclable heterogeneous catalyst for making coumarin-3-carboxylic acids (100% conversion) from the one-pot Knoevenagelintramolecular cyclization tandem reaction of substituted salicylaldehydes and Meldrum's acid in just 1 h at ambient conditions in methanol. The detailed reaction mechanism has been discussed with the help of theoretical calculations and experimental evidence.

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Section: ■ Experimental Sectionsupporting

confidence: 88%

CdO Nanostructures as Acid–Base Bifunctional Heterogeneous Catalysts for Making Coumarin-3-carboxylic Acids at Room Temperature

Kaur,

Mandal

2024

ACS Appl. Nano Mater.

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“…GO was suggested to enhance the photocatalytic activity of ZnO because of its great capability to dye adsorption and charge separation. Furthermore, the junction between Pd and ZnO was believed to effectively separate the photogenerated charges due to the metal–semiconductor diode effect. , …”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the junction between Pd and ZnO was believed to effectively separate the photogenerated charges due to the metal−semiconductor diode effect. 27,28 The great light absorption capability and high separation efficiency of photogenerated electron−hole pairs among a composite of TiO 2 , carbon, and Ag nanoparticles enhanced the photocatalytic efficiency of photodegradation of dyes compared with that of the pure TiO 2 nanofibers. 18 In the literature, the photocatalytic activity of the majority of photocatalysts was tested by different types of organic dyes, which are usually categorized according to their chromophores.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic Activity of Graphene Oxide/Zinc Oxide Nanocomposites with Embedded Metal Nanoparticles for the Degradation of Organic Dyes

2020

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Nanocomposite materials based on metal nanoparticles and graphene oxide (GO) have gained increasing attention for their wide range of potential applications in various materials science fields. In this study, an efficient photocatalyst based on GO/ ZnO nanocomposites with embedded metal nanoparticles was successfully synthesized via a simple one-pot method. The synthesized nanocomposites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. The photocatalytic activity of the synthesized nanocomposites was tested in the degradation of methylene blue (MB) dyes, as a model of water pollutants. A catalytic activity of 84% was achieved using a nanocomposite with a percentage of 3.125% GO, after 90 min sunlight irradiation. Furthermore, embedded copper and silver nanoparticles were used as dopants to study their effects on the activity of the photocatalyst. The GO−ZnO−Cu nanocomposite showed that the activity toward MB degradation was decreased by 50%, while a significant increase in the activity of MB degradation was achieved by the GO−ZnO−Ag nanocomposite. The removal efficiency of MB by the GO−ZnO−Ag nanocomposite reached 100% after 40 min of sunlight irradiation. Thus, the GO−ZnO−Ag nanocomposite has the potential to be an efficient adaptable photocatalyst for the photodegradation of organic dyes in industrial wastewater.

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“…Actually, CdS/CdS x Se 1− x axial heterostructure nanowire photodetectors have shown more superior photodetection properties than that of single component CdS or CdS x Se 1− x . However, the controllable synthesis of axial HNWs is elusive and there are only few reports to date . Different from the recent CdS/CdS x Se 1− x axial HNWs, which contain heavy‐metal Cd element and might be unfavorable for practical application.…”

Section: Introductionmentioning

confidence: 99%

1D ZnSSe‐ZnSe Axial Heterostructure and its Application for Photodetectors

Zheng

Liu

et al. 2019

Adv Elect Materials

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possessing high photocurrent gain, fast response speed, high photosensitivity, wide response wavelength, and multiband photodetection are highly desired. [1][2][3][4] For this purpose, nanowires with large surface-to-volume ratio and quantum confinement effect show huge advantages over the bulk and thin film counterparts for fabrication of high performance photodetectors. [5][6][7][8][9][10] Since the discovery of carbon nanotubes, there are many reports about the photodetectors based on various 1D inorganic semiconductor nanostructures. For example, Si, Ge, ZnO, Ga 2 O 3 , CdS, ZnSe, CdSe, GaN, GaAs, InAs, CsPbBr 3 , and CsPb 2 Br 5 nanowires/nanobelts were used to fabricate photodetectors and demonstrate excellent photoresponse properties. [11][12][13][14][15][16] However, it is still very challenging to obtain the broad spectral response and high responsivity in these single component nanowire photodetectors due to the constraint of bandgap engineering, light absorptivity, and photogenerated carriers transfer efficiency. [17,18] High-quality semiconductor heterostructure nanowires (HNWs) integration with multicomponent can increase the absorption ability and extend the photoresponse range effectively. Actually, CdS/CdS x Se 1−x axial heterostructure nanowire photodetectors have shown more superior photodetection properties than that of single component CdS or CdS x Se 1−x . However, the controllable synthesis of axial HNWs is elusive and there are only few reports to date. [19,20] Different from the recent CdS/CdS x Se 1−x axial HNWs, which contain heavy-metal Cd element and might be unfavorable for practical application. ZnSe and ZnS with direct bandgap of 2.7 and 3.6 eV at room temperature are promising semiconductor materials for optoelectronics application in the visible and ultraviolet region. [21][22][23] Compared to binary ZnSe and ZnS nanowires, the recent synthesis and optical properties characterization of ZnS x Se 1−x ternary alloy nanostructures demonstrate tunable bandgap and photoluminescence (PL) properties, [24,25] which are similar to CdS x Se 1−x . These results favor the synthesis of ZnS x Se 1−x /ZnSe HNWs that is more friendly to environment and human health. However, to the best of our knowledge, there is not any report about the ZnSe x S 1−x /ZnSe axial heterostructure due to the phase structure, lattice mismatch, and the melting point between ZnSe and ZnS, which makes the epitaxial growth of ZnSe along the Semiconductor heterostructure nanowires (HNWs) are excellent candidates for application in compact optoelectronics devices with high performance due to the heterojunction interface effect. However, the controllable fabrication of high-quality nano-heterostructures is elusive. In this paper, the controllable growth and optoelectronics device application of high-quality ZnS 0.49 Se 0.51 / ZnSe axial HNWs are reported. The as-synthesized HNWs are straight with uniform diameter distribution of 50-100 nm. Microstructural characterization reveals single crystal and abrupt heterojunction int...

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Branched CdO/ZnO Core/Shell Heterogeneous Structure and Its Enhanced Photoelectrocatalytic Performance

Cited by 17 publications

References 43 publications

CdO Nanostructures as Acid–Base Bifunctional Heterogeneous Catalysts for Making Coumarin-3-carboxylic Acids at Room Temperature

CdO Nanostructures as Acid–Base Bifunctional Heterogeneous Catalysts for Making Coumarin-3-carboxylic Acids at Room Temperature

Photocatalytic Activity of Graphene Oxide/Zinc Oxide Nanocomposites with Embedded Metal Nanoparticles for the Degradation of Organic Dyes

1D ZnSSe‐ZnSe Axial Heterostructure and its Application for Photodetectors

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