Cu₂O/Ag co-deposited TiO₂nanotube array film prepared by pulse-reversing voltage and photocatalytic properties

Abstract

In this experiment, CuO/Ag co-deposition TiO nanotube array (CuO-Ag-TNT) film was prepared on pure Ti substrate with the method of combining anodic oxidation and electrodeposition by pulse-reversing voltage power supply in the electrolyte of NHF, ethylene glycol, CuNO · 3HO and AgNO. The morphology, phase, chemical composition, photocatalytic property and mechanism of the nanotube array film were studied by means of scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, x-ray photoelectron spectroscopy, transmission electron microscopy, UV-vis diffuse reflectance spectra, photoluminescence and photocatalytic degradation under visible light. The results showed that the depositional CuO and Ag existed in two forms, being the small-particle dispersion and large-particle sedimentary phase in the nanotube arrays: CuO-Ag-TNTs for different doping amounts of Ag could be prepared by adjusting the concentration of AgNO and the reverse voltages; with changing of the doping amount of Ag, the band gap and photo-generated electron-hole pair recombination rate also changed, and under the conditions of annealing and the optimized process parameter, the band gap of the nanotube arrays narrowed 0.49 eV and the rate of electron and pair recombination decreased noticeably; the nanotube array film for the concentration of 0.5 cm ml degraded the methylene blue of 8 mg L, and the degradation rate reached above 98%. The co-deposition CuO-Ag-TNT film prepared by the one-step method performed well in the field of photocatalysis under visible light.

Dual Cocatalysts in TiO2 Photocatalysis

“…According to the elementary composition, cocatalysts can be classified into: noble metals (e.g., Pt, Au, Ag, Pd, and Rh), non‐noble metals (e.g., Cu and Ni), metal oxides (e.g., NiO, CoO x , MnO x , IrO x , CuO x , and RuO 2 ), metal hydroxides (e.g., Ni(OH) 2 , Cu(OH) 2 , and Co(OH) 2 ), metal sulfides (e.g., MoS 2 , WS 2 , CuS, and NiS), metal phosphides (e.g., Co 2 P, Ni 2 P, and MoP), and carbonaceous materials (e.g., graphene, carbon quantum dots, carbon nanotube, and graphdiyne) …”

“…Recently, several transition metal oxides, such as CoO x , MnO x , FeO x , RuO 2 , IrO x , CuO x , and NiO, have been developed as low‐cost and efficient cocatalysts for photocatalytic reactions. Generally, the role of metal oxides can be summarized as follows: i)Several types of heterojunctions (such as conventional type‐II heterojunction, p–n junction and direct Z‐scheme heterojunction) between TiO 2 and metal oxides can be formed, thus promoting the charge separation; ii)Metal oxides can act as reduction cocatalysts and oxidation cocatalysts, which trap the photogenerated electrons and holes, respectively, thus providing active sites for photocatalytic redox reactions; iii)Metal oxides can extend the absorption range from UV to visible light region.…”

“…Generally, Cu 2 O can be conjoined with noble metals such as Pt, Cu, Au, and Ag to offset their individual inadequacies. For instance, Pt and Cu 2 O NPs were coloaded on the surface of anatase TiO 2 nanocrystals .…”

UV-Vis-Induced Degradation of Phenol over Magnetic Photocatalysts Modified with Pt, Pd, Cu and Au Nanoparticles

“…Magnetic photocatalysts modified with Ag, Pt, Ag-Pd or Au particles have been studied in the photocatalytic removal of chlorophenol [ 19 ], and mainly in the reaction of organic dye removal such as rhodamine B [ 20 , 21 ] and methylene blue [ 12 , 22 ]. Although the effect of TiO 2 modified with noble and semi-noble metal nanoparticles in photo-oxidation of chlorophenol [ 19 ] and dyes [ 20 ] for magnetic photocatalysts and chlorophenol [ 23 , 24 ], toluene [ 25 , 26 , 27 ], pesticides [ 28 , 29 ], carbonic acid [ 30 , 31 ], and dyes [ 32 , 33 ] for metal-modified TiO 2 photocatalysts has been proved, the influence of the photocatalyst’s structure on the photocatalytic activity and the mechanism of photocatalytic reaction still needs clarification. Reaction intermediates and product formation pathways depend on the physicochemical properties of the photocatalyst as well as experimental conditions, e.g., reaction environment, aeration, concentration and type of organic compounds, irradiation source and temperature [ 34 , 35 , 36 , 37 ].…”

The Photocatalytic Properties and Mechanistic Study of ZnO,Ag Multiphase Co-Composited TiO2Nanotube Arrays Film Prepared by One-Step Anodization Method

“…Xi Kang et al 26 prepared Ag/N co-doped TiO 2 nanotube arrays z E-mail: chensy@smm.neu.edu.cn (TiO 2 TNAs) by anodic oxidation, Ag deposited on the surface of TiO 2 NTAs by photodeposition and post-treatment, the absorption of visible light enhanced by N-doing, the surface plasma resonance effect of Ag improved the separation of electron-hole pairs. In previous work of our group, Qi Ding et al 27 prepared Cu 2 O/Ag co-deposition TiO 2 nanotube array film with the method of combining anodic oxidation and electrodeposition by pulse-reversing voltage power supply in the electrolyte of NH 4 F, ethylene glycol, CuNO 3 • 3H 2 O and AgNO 3 . The results showed that Cu 2 O and Ag existed in smallparticle dispersion and large-particle sedimentary phase two forms in the nanotube arrays, the photocatalysis properties, the bandgap and photogenerated electron-hole pairs recombination rate also changed obviously.…”