Preparation of flower‐like Cu₂O/ZnO for removal of dyes from aqueous medium

Abstract

Flower‐like Cu2O/ZnO was prepared by hydrothermal method with the reducing agent of glucose for removal of dyes in aqueous medium. As‐prepared samples were characterized by FE‐SEM, XRD, and TEM. Flower‐like Cu2O/ZnO could both photodegrade Tartrazine (TA) under UV and visible lights with the removal efficiencies of 85.3 and 96.1 %, respectively, and adsorbed TA with the removal efficiency of 77.5 %. The effects of adsorbent dosage, dye concentration, and pH solution on adsorption of dyes were investigated. The kinetic adsorption of TA on flower‐like Cu2O/ZnO was studied by pseudo‐first‐order and pseudo‐second‐order models. In addition, the performance of as‐prepared material was evaluated by cyclic test and adsorption of other dyes such as methylene blue, Janus green B and Congo red.

Preparation of carnation-like Ag-ZnO composites for enhanced photocatalysis under visible light

“…The hydrothermal process (90 °C and 24 h) was applied. The reddish-brown precipitate obtained after the hydrothermal process was filtered, dried at 60 °C for 24 h, then calcined at 400 °C about 2 h and at 2 °C min -1 for heating rate [10].…”

“…The limitations like the high rate recombination of electron-hole and weak absorption of visible light of pure ZnO lead to inefficient use of visible light for its photocatalytic activity. However, the photocatalytic performance of ZnO could be upgraded by manipulating the structural morphology and reducing the rate of recombination of electron-hole, which were made through surface modification of metal/non-metal ions [10][11][12][13], coupled with semiconductors and carbon-based materials [14][15][16][17], and deposition of precious metals [18][19][20][21]. Studies have shown that the improvement of photocatalytic activity can be from the following causes: (i) precious metals can work as traps to separate electrons and holes enhancing quantum efficiency [22], (ii) relatively high adsorption capacity in certain wavelength regions of nanoparticles of precious metals due to the surface plasmon resonance (LSPR) [20,23], and (iii) the presence of the Schottky barrier due to surface interactions promotes separation of charged particles [5,20,24].…”

Preparation of Hierarchical Structure Au/ZnO Composite for Enhanced Photocatalytic Performance: Characterization, Effects of Reaction Parameters, and Oxidizing Agent Investigations

“…Amongst them, doping ZnO nanomaterials by noble metals is the most suitable method because it could improve the photocatalytic activity of the semiconductor through these three pathways above at the same time. Several studies have demonstrated that the Schottky barrier will be formed when precious metal nanoparticles are directly anchored on the surface of ZnO [26, 38, 39]. Since the conduction band energy level of ZnO is larger than the Fermi energy of the precious metal, the separation of charge carriers is enhanced.…”

Facile Controlling of the Physical Properties of Zinc Oxide and Its Application to Enhanced Photocatalysis

“…erefore, ZnO has been widely used in many fields, such as adsorption, paint, cosmetic, superconductor, and catalyst [7][8][9][10][11][12]. As an effective photocatalyst in the degradation of persistent organic compounds [13][14][15] and catalyst support [16,17], ZnO should have a sufficient structure area and morphology to allow the diffusion of active species and electron transfer [18]. Well-designed ZnO has shown high performance in the degradation of dyes as promised photocatalyst [19,20].…”