Photocatalytic Activity Of Cu Research Articles

Photocatalytic activity of Cu doped TiO 2 nanoparticles and comparison of two main doping procedures

In this reported work, TiO 2 nanoparticles containing anatase-rutile and pure rutile phases were prepared by sol-gel and hydrolysis in acidic solution methods, respectively. Two general procedures, doping during synthesis (DDS) via a hydrolysis method and doping on the provided TiO 2 nanoparticles (DOP) that is performed by the impregnation method have been studied by doping copper to these nanoparticles. The photocatalytic activity was evaluated by photodegradation of C.I. Acid Red 27 as a model contaminant. The prepared samples were characterised by X-ray diffraction, atomic absorption flame emission spectroscopy and scanning electron microscopy. It is found that the photosensitised degradation activity can be enhanced by doping an appropriate amount of Cu. Photocatalytic activity results indicated that samples that have been doped by the DDS procedure show higher photocatalytic efficiency than samples doped by the DOP procedure.

First principle study of CuN, Cu and N-doped anatase TiO2

Cu, N and CuN-doped anatase TiO2 are studied using density functional theory (DFT). It is found the band gap decreases after CuN co-doped. The intensity of adsorption spectra increases in the following order: CuN codoped⪢Cu-doped⪢N-doped⪢pure anatase in visible region, indicating that the electrons on the valence band easily transit to the conduction band. In other words, theoretic calculation shows that the photocatalytic activity of CuN co-doped is higher than that of the corresponding single Cu or N-doped.

Preparation of Cu-loaded SrTiO3 nanoparticles and their photocatalytic activity for hydrogen evolution from methanol aqueous solution

Cu-loaded SrTiO3 nanoparticles (Cu–SrTiO3) were prepared using a simple in situ photo-deposition method and their photocatalytic activity for hydrogen evolution from methanol aqueous solution was evaluated. The results characterized with XRD, TEM, XPS and EDX indicated that the as-synthesized sample was composed of metallic Cu and cubic SrTiO3, and the metallic Cu was homogeneously loaded on the surface of SrTiO3 nanoparticles. Under UV light irradiation, Cu–SrTiO3 displayed much higher photocatalytic activity for hydrogen evolution and excellent stability in comparison with pure SrTiO3 nanoparticles. The results further confirmed that the efficient separation of photogenerated electron/hole pairs was critical for the enhanced photocatalytic activity of Cu–SrTiO3. Moreover, the rate of hydrogen evolution of 0.5wt.% Cu–SrTiO3 is comparable with that of 0.5wt.% Pt–SrTiO3 photocatalyst under optimum conditions, implying that the metallic Cu is an efficient alternative to Pt as a co-catalyst on SrTiO3. The high photocatalytic activity, low cost and chemical stability mean that the Cu-loaded SrTiO3 is a potential catalyst for the photocatalytic hydrogen evolution from methanol aqueous solution.

The Photo-Catalytic Activity of Cu<sup>2+</sup>-Doped TiO<sub>2</sub> and Applications in the Self-Cleaning Performance of Textile Wall Fabrics

TiO2 photocatalyst and copper-doped titania (Cu/TiO2) photocatalyst were prepared and both photocatalysts were used in the self-cleaning finishing of wall fabrics. XRD showed that the nanometer materials and textile wall fabrics were a good combination. By comparing the self-cleaning effects of two kinds of photocatalysts, the results demonstrate that textile wall fabrics finished with Cu2+-doped TiO2 photocatalyst have better self-cleaning effect under visible light.

Photocatalytic Activity of Cu<SUB>2</SUB>O and Bilayer Cu<SUB>2</SUB>O/TiO<SUB>2</SUB> Films Prepared by Magnetron Sputtering

Photocatalytic Activity of Cu<SUB>2</SUB>O and Bilayer Cu<SUB>2</SUB>O/TiO<SUB>2</SUB> Films Prepared by Magnetron Sputtering

Synthesis and Photocatalytic Activity of Cu<SUB>2</SUB>O/TiO<SUB>2</SUB> Double Wall Nanotube Arrays

Synthesis and Photocatalytic Activity of Cu<SUB>2</SUB>O/TiO<SUB>2</SUB> Double Wall Nanotube Arrays

A cuprous oxide–reduced graphene oxide (Cu2O–rGO) composite photocatalyst for hydrogen generation: employing rGO as an electron acceptor to enhance the photocatalytic activity and stability of Cu2O

Photocorrosion, that causes rapid deactivation of Cu(2)O photocatalysts, was addressed by incorporating this oxide in a composite with reduced graphene oxide which acts as an electron acceptor to extract photogenerated electrons from Cu(2)O. Cu(2)O-rGO composite engineering also allows enhancing significantly photocatalytic activities of Cu(2)O for H(2) generation.

Influence of polarity of the peripheral substituents of porphyrin molecules on the photocatalytic activity of Cu(ii) porphyrin modified TiO2 composites

Two novel porphyrins, 5,10,15-tri-phenyl-20-[4-(2-(4-formoxyl) phenoxy)ethoxy]phenyl porphyrin and 5,10,15-tri-phenyl-20-[4-(2-(4-hydroxyimino) phenoxy)ethoxy]phenyl porphyrin, and their corresponding copper(II) complexes were synthesized and spectroscopically characterized. The Cu(II) porphyrin–TiO2 composites were also prepared and characterized. The photoactivity of the composites was investigated by carrying out the degradation of 4-nitrophenol (4-NP) in aqueous solution under UV-visible light. It was found that the photoactivity of Cu(II) porphyrin–TiO2 composites was evidently influenced by the interaction between porphyrin molecules and hydroxyls anchored on the TiO2. Furthermore, the photoactivity of Cu(II) porphyrin–TiO2 composites was also affected by dispersion of composites in 4-NP solution.

Formation of Cu0 in Cu2O under light irradiation and subsequent accelerated decoloration to MO aqueous solution

In the photocatalytically decoloring process of methyl orange (MO) aqueous solution by Cu 2 O polycrystalline film, Cu + was reduced to Cu 0 and oxidized to Cu 2+ simultaneously. The adsorption of MO molecules onto the Cu 2 O film was deduced by complexation reactions between Cu 0 and the MO molecules, thus enhancing the decoloration rate of the aqueous solution. This research demonstrates that, apart from the photocatalytic activity of Cu 2 O, Cu 0 plays an important role in the bleaching process of MO solution. The results also suggest the application of metallic copper as a candidate for treatment of textile dyeing wastewater. ► In photocatalytically decoloring MO solution by Cu 2 O, Cu + was reduced to Cu 0 . ► Complexation reaction between Cu 0 and MO molecules enhanced decoloration rate. ► Decoloration was due to combined action of photocatalysis and complexation. ► Complexation reaction deduced formation of Cu 2 O.

Architecture of Cu 2O@TiO 2 core–shell heterojunction and photodegradation for 4-nitrophenol under simulated sunlight irradiation

A Cu 2O@TiO 2 core–shell heterojunction photocatalyst was prepared by an in situ hydrolysis and crystallization method. The as-prepared catalyst was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy and photoluminescence (PL) spectroscopy. Under simulated sunlight irradiation, it exhibited high photocatalytic activity and stability for 4-nitrophenol (4-NP) degradation. Compared with neat Cu 2O and Cu 2O/TiO 2(PM) prepared by physical mixing, the heightened photocatalytic activity of Cu 2O@TiO 2 was attributed to the improvement of charge separation since large close interface was formed between the two semiconductors. The in situ method may generally be applied to develop other core–shell heterojunction photocatalysts.

Preparation of Cu 2O/TiO 2 composite porous carbon microspheres as efficient visible light-responsive photocatalysts

In this paper, Cu 2O/TiO 2 composite porous microspheres were prepared in the absence of templates and additives by a simple hydrothermal method using Cu(CH 3COO) 2·H 2O and (NH 4) 2TiF 6 as precursors. The photocatalytic activity of the samples was evaluated by the photo-degradation of methylene blue (MB) aqueous solution under the visible-light illumination. To the best of our knowledge, this is the first report on the preparation and photocatalytic activity of Cu 2O/TiO 2 composite porous microspheres with a template-free hydrothermal method. This work may provide new insights into preparing other inorganic porous microspheres.

Photochemical synthesis of copper sulphide/titanium oxide photocatalyst

Copper sulphide powder was obtained by the photochemical synthesis and thin films were developed by doctor blade deposition of Cu x S and Cu x S/TiO 2 composites with photocatalytic properties. The photochemical process could be adjusted to prepare Cu x S with different photocatalytic activities by changing the CuSO 4:Na 2S 2O 3 molar ratio while keeping other conditions unchanged (solutions pH, solutions volume, irradiation time and intensity). The powder and thin film properties were characterized in terms of: the Fourier transform infra-red (FTIR), the X-ray diffraction (XRD), UV–vis spectroscopy, atomic force microscopy (AFM). The photocatalytic process using Cu x S and coupled Cu x S/TiO 2 thin film semiconductors in the dyes photodegradation (methyl orange and methylene blue) was investigated. The photocatalytic activity of Cu x S/TiO 2 nanocomposites depends on the Cu x S:TiO 2 ratio; the best results correspond to the Cu x S/TiO 2 (Cu x S:TiO 2 = 3:7) photocatalysts, with high efficiency (almost 99%) after 300 min for methyl orange, respectively after 180 min for methylene blue degradation, under UV irradiation, when H 2O 2 is added in photocatalytic process. The semiconductors association and the films homogeneity limit the electron–hole recombination, resulting in good efficiency in dyes photodegradation even under visible light irradiation.

Enhanced photocatalytic activity of flowerlike Cu 2O/Cu prepared using solvent-thermal route

Cu 2O/Cu nanocomposites (NCs) with flowerlike nano-architecture were prepared using template-free stepwise solvent-thermal synthesis route with Cu(NO 3) 2·3H 2O as a precursor. With the precursor concentration increasing gradually from 0.01 to 0.1 M, the morphology of the NCs evolves from nano-flower to microsphere. The content of Cu in the NCs can be easily controlled by adjusting the concentration of precursor and synthesis time. Using photocatalytic degradation of monoazo dye Procion Red MX-5B (PR) and phenol as the probe molecules under visible-light illumination, we have investigated the influence of Cu on the photocatalytic activity of Cu 2O. When the content of Cu lies in the range of 27–71 wt%, the samples exhibit higher photocatalytic performance, indicating that these flowerlike Cu 2O/Cu NCs are promising candidates for pollutant processing.

Growth, structure and photocatalytic properties of hierarchical Cu–Ti–O nanotube arrays by anodization

Recently p-type Cu–Ti–O nanotubes have been explored in water-splitting photoelectrochemical pn-junction diodes to significantly improve the photoconversion efficiency. We reported on the growth and characterization of Cu–Ti–O nanotube arrays by anodizing directly Cu–Ti (30:70 wt%) alloy substrate. As-anodized hierarchical Cu–Ti–O nanotube arrays consist of two distinct Ti-rich and Cu-rich nanotube regions. It was found that mechanical stresses induced by copper doping resulted in the difference in the microstructure evolution of Cu-rich and Ti-rich regions. The oxygen vacancies induced by the high concentration Cu dopant into the Cu–Ti–O nanotube play a crucial role in determining the phase stabilization of anatase phase. The absorption edge of TiO 2 nanotube arrays was extended into the visible region by Cu doping. In degrading Methyl orange (MO), 21.2% MO was removed using Cu–Ti–O nanotube arrays after 240 min UV illumination. This result indicates the photocatalytic activity of Cu–Ti–O nanotube arrays to MO is reasonably high.

ChemInform Abstract: Photocatalytic Activity of Cu2O Nanoparticles Prepared Through Novel Synthesis Method of Precursor Reduction in the Presence of Thiosulfate.

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Preparation and photocatalytic activity of Cu 2+-doped TiO 2/SiO 2

Cu 2+-doped nanostructured TiO 2-coated SiO 2 (TiO 2/SiO 2) particles were prepared by the layer-by-layer assembly technique and their photocatalytic property was studied. TiO 2 colloids were synthesized by the sol-gel method using TiOSO 4 as a precursor. The experimental results showed that TiO 2 nanopowders on the surface of SiO 2 particles were well distributed and compact. The amount of TiO 2 increased with the increase in coating layers. The shell structure appeared to be composed of anatase titania nanocrystals at 550°C. The 2-layer coated TiO 2 particles on the surface showed a higher degradation rate compared with all the different-layer samples. The photocatalytic activity of Cu 2+-doped TiO 2/SiO 2 was higher than that of undoped TiO 2/SiO 2. The optimum dopant content was about 0.10wt%.

Photo-Catalytic Activity of Cu<sub>2</sub>O Films with Various Crystal Structures Prepared by DC Reactive Magnetron Sputtering

The direct current (DC) reactive magnetron sputtering of a metal copper target in oxygen-argon mixed atmospheres to produce thin films of crystalline copper oxides was described. The sputtering pressure, sputtering power and oxygen flow rate were established in order to control the structures and properties of Cu2O films. The as-deposited Cu2O films with various crystal structures have high visible absorption and photo-catalytic activity under visible light irradiation. The photo-catalytic properties of Cu2O films are affected by not only the crystal structure but also the surface morphology.

Preparation, characterization and photocatalytic properties of Cu-loaded BiVO 4

A series of Cu-loaded BiVO 4 (Cu–BiVO 4) catalysts were prepared by impregnation method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS) and special surface area. The photocatalytic activities of Cu–BiVO 4 catalysts for the degradation of methylene blue (MB) were found to depend largely on the Cu content and the calcination temperature. The optimum Cu loading and calcination temperature were found to be 5 at.% and 300 °C, respectively. The results of XPS and SEM analysis indicated that Cu, CuO in this case, was dispersed on the surface of BiVO 4. The results of DRS analysis showed that the Cu–BiVO 4 series catalysts had significant optical absorption in the visible region between 550 and 800 nm and found that the absorption intensity increased with the enhancement of Cu content. An efficient N-demethylation of MB using Cu–BiVO 4 catalyst (5 at.% Cu content) calcined at 300 °C was also observed.

Investigations on the Effect of Mn Ions on the Local Structure and Photocatalytic Activity of Cu(I)−ZSM-5 Catalysts

The introduction of Mn ions into Cu(I)-ZSM-5 was found to lead to an enhancement of the photocatalytic activity for the direct decomposition of N2O into N2 and O2 at 298 K. Various in-situ techniques such as ESR, photoluminescence, XAFS as well as a combination of CO-FT-IR and CO-TPD measurements revealed that the accommodation of Mn ions within ZSM-5 zeolite cavities significantly affects the location sites of the ion-exchanged Cu(II) ions as well as the local structure of the Cu(I) ion species formed by evacuation at high temperatures. Moreover, the introduction of Mn ions into ZSM-5 led to an increase in the amount of 3-coordinated Cu(I) species at the main channel of the zeolite, playing a major role as the active species for the photocatalytic decomposition of N2O into N2 and O2.

Photocatalytic activity of Cu 2O/TiO 2, Bi 2O 3/TiO 2 and ZnMn 2O 4/TiO 2 heterojunctions

Cu 2O/TiO 2, Bi 2O 3/TiO 2 and ZnMn 2O 4/TiO 2 heterojunctions were studied for potential applications in water decontamination technology and their capacity to induce an oxidation process under VIS light. UV–vis spectroscopy analysis showed that the junctions-based Cu 2O, Bi 2O 3 and ZnMn 2O 4 are able to absorb a large part of visible light (respectively, up to 650, 460 and 1000 nm). This fact was confirmed in the case of Cu 2O/TiO 2 and Bi 2O 3/TiO 2 by photocatalytic experiments performed under visible light. A part of the charge recombination that can take place when both semiconductors are excited was observed when a photocatalytic experiment was performed under UV–vis illumination. Orange II, 4-hydroxybenzoic and benzamide were used as pollutants in the experiment. Photoactivity of the junctions was found to be strongly dependent on the substrate. The different phenomena that were observed in each case are discussed.