A twice liquid arc discharge approach for synthesis of visible-light-active nanocrystalline Ag:ZnO photocatalyst

Abstract

Ag:ZnO hybrid nanostructures were successfully prepared by a twice arc discharge method in liquid. The visible light photocatalytic activities were successfully demonstrated for the degradation of Rhodamine B (Rh. B), Methyl orange (MO), and Methylene blue (MB) as standard organic compounds under the irradiation of 90 W halogen light for 2 h. The Ag:ZnO nanostructures were characterized by X-Ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and ultraviolet-visible absorption spectroscopy (UV-Vis). The results revealed that the Ag:ZnO nanostructures extended the light absorption spectrum toward the visible region and significantly enhanced the Rh. B photodegradation under visible light irradiation. 3 mM Ag:ZnO nanostructures exhibited highest photocatalytic efficiency. It has been confirmed that the Ag:ZnO nanostructures could be excited by visible light (E < 3.3 eV). The significant enhancement in the Ag:ZnO nanostructures photocatalytic activity under visible light irradiation can be ascribed to the effect of physisorbed noble metal Ag by acting as electron traps in ZnO band gap. A mechanism for photocatalytic degradation of organic pollutant over Ag:ZnO photocatalyst was proposed based on our observations.

A study on the mechanism for the interaction of light with noble metal-metal oxide semiconductor nanostructures for various photophysical applications

“…In recent years, various nanostructures of ZnO-noble metal have been successfully prepared using different methods. Noble metal NPs deposited on ZnO NPs, 61,79,80,86,87,[155][156][157][158][159][160][161][162][163][164] nanorods, 62,69,91,96,[165][166][167][168][169][170] films, 67,171,172 spheres, [173][174][175] flowers 68,85,[176][177][178] and other configurations were widely reported. 84,[179][180][181] Metal-ZnO nanocomposites are fabricated by depositing, growing or attaching metal NPs onto the surface of prefabricated ZnO nanostructures.…”

Development of Ag/ZnO nanorods and nanoplates at low hydrothermal temperature and time for acetone sensing application: an insight into spillover mechanism

“…Since the discovery of ZnO and its usefulness in varieties of applications, it has attracted increasing attention as promising semiconducting material [1][2][3][4][5]. Apart from gas sensing, ZnO has attracted high technological applications, like photodetectors, photodiodes, surface acoustic wave filters, solar cells, photonic crystals, LEDs, optical waveguides, due to its wide direct band gap (3.3 eV) and large excitation binding energy (60 meV) [6][7][8][9][10][11][12]. In the state of the art, doping of noble metals like gold (Au), platinum (Pt), ruthenium (Ru), nickel (Ni), palladium (Pd), gallium (Ga), silver (Ag) and their combinations showed significant improvement in ZnO-based gas sensor [13][14][15][16][17][18][19][20].…”

Opto-electrical properties and chemisorption reactivity of Ga-doped ZnO nanopagodas

“…1 Recently zinc oxide (ZnO) nanostructures have attracted global research interest in applications such as laser diodes, 2,3 light-emitting diodes, 4,5 solar cells, 6 eld effect transistors, 7 eld-emission displays, 8,9 photodetectors, [10][11][12] and photocatalysts. [13][14][15][16] Many efforts have focused on the doping of ZnO with selected elements in order to achieve desirable optical, electrical, and magnetic properties that are important for device applications. [17][18][19] ZnO, a II-VI semiconductor with a wide direct energy band gap of 3.37 eV and a large exciton binding energy of 60 meV, 2 is a good candidate for ultraviolet (UV) photodetectors (PDs).…”