Photocatalytic Activity Of Er3 Research Articles

Rapid microwave-assisted solvothermal synthesis and visible-light-induced photocatalytic activity of Er3+-doped BiOI nanosheets

BiOI nanosheet photocatalysts with different Er3+ doping contents were rapidly synthesized by microwave-assisted solvothermal method using water and ethylene glycol as a mixed solvent. All synthesized photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), N2 adsorption, photoluminescence (PL) spectra, and UV–vis diffuse reflectance spectroscopy (DRS). The photocatalytic activities of the as-prepared Er3+-doped BiOI nanosheets were investigated by the photodegradation of Rhodamine B (RhB) dye in aqueous solution under visible light irradiation. The photodegradation results indicate the optimal doping of 1 mol.% Er3+ in BiOI nanosheets (doping content is from 0 mol.% to 4 mol.%) to be the most beneficial for photodegradation of RhB. 1Er-BiOI nanosheets also possesses good photocatalytic activity for representative anionic methyl orange (MO). From the scavenger testing results, the reactive species of holes (h+) and superoxide radical anions (O2−) show major impacts on the photodegradation progress of RhB and MO dyes over 1Er-BiOI photocatalyst under visible light irradiation.

Photocatalytic degradation of organic dyes by Er3+: YAlO3/Co- and Fe-doped ZnO coated composites under solar irradiation

In this work, the Er3+: YAlO3/Co- and Fe-doped ZnO coated composites were prepared by the sol-gel method. Then, they were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). Photo-degradation of azo fuchsine (AF) as a model dye under solar light irradiation was studied to evaluate the photocatalytic activity of the Er3+: YAlO3/Co- and Fe-doped ZnO coated composites. It was found that the photocatalytic activity of Co- and Fe-doped ZnO composites can be obviously enhanced by upconversion luminescence agent (Er3+: YAlO3). Besides, the photocatalytic activity of Er3+: YAlO3/Fe-doped ZnO is better than that of Er3+: YAlO3/Co-doped ZnO. The influence of experiment conditions, such as the concentration of Er3+: YAlO3, heat-treatment temperature and time on the photocatalytic activity of the Er3+: YAlO3/Co- and Fe-doped ZnO coated composites was studied. In addition, the effects of solar light irradiation time, dye initial concentration, Er3+: YAlO3/Co- and Fe-doped ZnO amount on the photocatalytic degradation of azo fuchsine in aqueous solution were investigated in detail. Simultaneously, some other organic dyes, such as Methyl Orange (MO), Rhodamine B (RM-B), Acid Red B (AR-B), Congo Red (CR), and Methyl Blue (MB) were also studied. The possible excitation principle of Er3+: YAlO3/Co- and Fe-doped ZnO coated composites under solar light irradiation and the photocatalytic degradation mechanism of organic dyes were discussed.

Sol–gel-hydrothermal synthesis of Er3+:Y3Al5O12/Pt–TiO2 membrane and visible-light driving photocatalytic hydrogen evolution from pollutants

A novel visible-light photocatalyst, Er3+:Y3Al5O12/Pt–TiO2 membrane, was prepared via sol–gel–hydrothermal method on glass substrates as a support. X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX) were used to reveal the crystallinity, surface morphology and chemical composition of the prepared Er3+:Y3Al5O12/Pt–TiO2 membrane. The catalytic activity of Er3+:Y3Al5O12/Pt–TiO2 membrane was examined through the photocatalytic hydrogen evolution from some pollutants, including phenol, glycerol and Na2S/Na2SO3, which were used as electron donors, under visible-light irradiation. Furthermore, some influence factors, such as mass ratio, pre-treatment temperature and used times, on the photocatalytic activity of Er3+:Y3Al5O12/Pt–TiO2 membrane were studied. The experimental results showed that the Er3+:Y3Al5O12/Pt–TiO2 membrane is a good and broad-spectrum photocatalyst in visible-light photocatalytic hydrogen evolution with simultaneous pollutant solution treatment.

Study on photocatalytic activity of Er3+:YAlO3/TiO2 composite films supported on electrically conductive glass (FTO) in visible-light photocatalytic degradation of organic dye

Er3+:YAlO3/TiO2 composite films were prepared via a sol–gel dip-coating method by using electrically conductive glass as a supporter, which were used as photocatalyst in the degradation of dyes under simulated visible-light radiation. This improvement was attributed two sides, one side was due to the presence of Er3+:YAlO3 as up-conversion luminescence agent mixed with TiO2 to solve the problem of low activity of TiO2 to visible-light. On the other side, in virtue of reducing the recombination rate between photogenerated electron–hole pairs the conductive glass was used as electron transfer. X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX) were performed to reveal the crystallinity, surface morphology and chemical composition of the prepared Er3+:YAlO3/TiO2 composite films. Its photocatalytic activity was examined through the degradation of some organic dyes under simulated visible-light irradiation. The degradation process of organic dyes was monitored by UV–vis spectrophotometer. Furthermore, some main influence factors on the photocatalytic activity of Er3+:YAlO3/TiO2 composite film such as Er3+:YAlO3/TiO2 mass ratio, layer number, heat-treated temperature and heat-treated time were studied. The recycling used times and organic dye kinds were also included in consideration. Finally, it can be predicted that the Er3+:YAlO3/TiO2 composite film plays a good and broad-spectrum photocatalytic activity to treat various organic dye wastewater on practical application.

Preparation of Er3+:Y3Al5O12/TiO2 composite film and application in visible light photocatalytic degradation of organic dyes

In this work, to solve the problem of low sensitivity of titanium dioxide (TiO2) to visible light, the Er3+:Y3Al5O12 as up-conversion luminescence agent was mixed with TiO2 and then Er3+:Y3Al5O12/TiO2 composite film, a novel visible light photocatalyst, was obtained through sol–gel dip-coating method. The Er3+:Y3Al5O12/TiO2 composite film was characterized by X-ray diffraction and scanning electron microscope. Its photocatalytic activity was examined through the degradation of some organic dyes under visible light irradiation. The degradation process of organic dyes was monitored by UV–vis spectrophotometer. Furthermore, some main influence factors on the photocatalytic activity of Er3+:Y3Al5O12/TiO2 composite film such as Er3+:Y3Al5O12/TiO2 mass ratio, layer number, heat-treated temperature, and heat-treated time were studied. The results indicate that three-layer Er3+:Y3Al5O12/TiO2 composite film with 0.3:1 mass ratio heat treated at 500°C for 60 min displays a high photocatalytic activity during visible light photocatalytic degradation of Azo Fuchsine. The recycling used times were also included in consideration. Finally, it can be predicted that the Er3+:Y3Al5O12/TiO2 composite film displays a good and broad-spectrum photocatalytic activity for degradation of most organic dyes.

Preparation of Er3+:Y3Al5O12/TiO2 composite film and influence of layer number and layer sequence on the visible-light photocatalytic activity

In this work, the Er3+:Y3Al5O12 as up-conversion luminescence agent was mixed with TiO2 and the corresponding Er3+:Y3Al5O12/TiO2 composite films were prepared on the one-sided surface of treated sheet glass through sol-gel dip-coating method. The prepared Er3+:Y3Al5O12/TiO2 composite films were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Their photocatalytic activities were examined through the degradation of some organic dyes under visible-light irradiation. The degradation process of organic dyes was monitored by UV-Vis spectrophotometer. Furthermore, some main influence factors on the visible-light photocatalytic activity of Er3+:Y3Al5O12/TiO2 composite film such as heat-treatment temperature and heat-treatment time were studied. The results indicate that three layer Er3+:Y3Al5O12/TiO2 composite films with one Er3+:Y3Al5O12/TiO2 composite film (as first layer close to sheet glass) and two pure TiO2 film (as second and third layers) display a higher visible-light photocatalytic activity during photocatalytic degradation of Azo Fuchsine. In addition, the results showed that the visible-light photocatalytic activity of Er3+:Y3Al5O12/TiO2 composite film related to the layer number and layer sequence on the sheet glass. Perhaps, the research results may offer some meaningful references for developing solar energy continuous flow wastewater treatment reactor.

Enhancement of solar light photocatalytic activity of TiO2-CeO2 composite by Er3+:Y3Al5O12 in organic dye degradation

The Er3+:Y3Al5O12, as an upconversion luminescence agent which is able to transform the visible part of the solar light to ultraviolet light, was prepared by nitrate-citrate sol-gel method. A novel solar light photocatalyst, Er3+:Y3Al5O12/TiO2-CeO2 composite was synthesized using ultrasonic treatment. The X-ray diffraction (XRD) and scanning election microscopy (SEM) were used to characterize the structural morphology of the Er3+:Y3Al5O12/TiO2-CeO2 composite. In order to evaluate the solar light photocatalytic activity of Er3+:Y3Al5O12/TiO2-CeO2 composite, the Azo Fuchsine dye was used as a model organic pollutant. The progress of the degradation reaction was monitored by UV-Vis spectroscopy and ion chromatography. The key influences on the solar light photocatalytic activity of Er3+:Y3Al5O12/TiO2-CeO2 were studied, such as Ti/Ce molar ratio, heat-treatment temperature and heat-treatment time. Otherwise, the effects of initial dye concentration, Er3+:Y3Al5O12/TiO2-CeO2 amount, solar light irradiation time and the nature of the dye on the solar light photocatalytic degradation process were investigated. It was found that the solar light photocatalytic activity of Er3+:Y3Al5O12/TiO2-CeO2 composite was superior to Er3+:Y3Al5O12/TiO2 and Er3+:Y3Al5O12/CeO2 powder in the similar conditions.

Electrospun nanofibers of Er3+-doped TiO2 with photocatalytic activity beyond the absorption edge

Er3+-doped TiO2 nanofibers with different Er3+ contents were prepared via electrospinning and characterized by X-ray diffraction, scanning electron microscopy, ultraviolet–visible diffuse reflectance spectroscopy and photocurrent measurement. Photocatalytic activities of the as-prepared samples were evaluated by the decolorization of methyl orange aqueous solution under simulated solar light irradiation. The results indicated that the photocatalytic activity of Er3+-doped TiO2 nanofibers was much higher than that of the undoped one, and the optimal dosage of Er3+ at 1mol% achieved the highest degradation rate. Moreover, the photocatalytic activity of Er3+-doped TiO2 nanofibers under the irradiation of light with the wavelength beyond the absorption edge of TiO2 was explored by the decolorization of a dye, rhodamine B and the photodegradation of a typical colorless pollutant, phenol. The results further revealed the mechanism of the enhanced photocatalytic activity through Er3+ doping in TiO2 nanofibers.

The improvement of solar photocatalytic activity of ZnO by doping with Er3+:Y3Al5O12 during dye degradation

The Er3+:Y3Al5O12, an upconversion luminescence agent, which is able to transform the visible light to ultraviolet light, was synthesized by nitrate-citric acid method. And then, a novel photocatalyst, Er3+:Y3Al5O12/ZnO composites, was prepared by ultrasonic dispersing and liquid boil method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the structural morphology and surface properties of the Er3+:Y3Al5O12/ZnO. Azo Fuchsine dye was selected as target organic pollutant to inspect the photocatalytic activity of Er3+:Y3Al5O12/ZnO. The key parameters affecting the photocatalytic activity of Er3+:Y3Al5O12/ZnO, such as Er3+:Y3Al5O12 content, heat-treatment temperature and heat-treatment time, were studied. In addition, the effects of dye initial concentration, Er3+:Y3Al5O12/ZnO amount and solar light irradiation time were also reviewed, as well as the photocatalytic activity in degradation of other organic dyes were compared. It was found that the photocatalytic activity of Er3+:Y3Al5O12/ZnO was much superior to pure ZnO under the same conditions. Thus, the Er3+:Y3Al5O12/ZnO is a useful photocatalyst for the wastewater treatment because it can efficiently utilize solar light by converting visible light into ultraviolet light.

Preparation of Er3+:Y3Al5O12/TiO2‐ZnO composite and application of solar energy in photocatalytic degradation of organic dyes

The Er3+:Y3Al5O12, which is able to transform the visible light from solar light into ultraviolet light as an upconversion luminescence agent, was prepared by nitrate‐citrate acid and heat‐treated method. And then, a novel photocatalyst, Er3+:Y3Al5O12/TiO2‐ZnO composite, which could effectively utilize the solar energy, was synthesized by ultrasonic dispersion and liquids boil method. In succession, X‐ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the structural morphology of the Er3+:Y3Al5O12/TiO2‐ZnO composite. And the degradation performances were also tested by UV‐vis spectrum and Ion chromatograph. To inspect the photocatalytic activity of Er3+:Y3Al5O12/TiO2‐ZnO composite, the Azo Fuchsine dye as target organic pollutant was degraded under solar light irradiation. The key impact parameters on the photocatalytic activity of Er3+:Y3Al5O12/TiO2‐ZnO such as Ti/Zn molar ratio, heat‐treated temperature and heat‐treated time were studied. Otherwise, the effects of dye initial concentration, Er3+:Y3Al5O12/TiO2‐ZnO, solar light irradiation time and other organic dyes were also investigated. It was found that the photocatalytic activity of Er3+:Y3Al5O12/TiO2‐ZnO composite was superior to TiO2‐ZnO powder in the similar system. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 697–704, 2013

Photocatalytic activity of Er3+, Yb3+ doped Bi5O7I

As upconversion agents, Er3+, Yb3+ were doped into Bi5O7I photocatalyst to improve its photocatalytic activity. Rhodamine B (RhB) and phenol were selected as model pollutants to evaluate the photocatalytic activity of the Bi5O7I under visible light irradiation (λ > 420 nm) and simulated solar light irradiation (λ > 290 nm), respectively. It was found that the photocatalytic activity of the Er3+:Yb3+ doped Bi5O7I was much higher than that of pure Bi5O7I and corresponding mechanism was discussed.

Preparation of Er3+:YAlO3/Fe-doped ZnO composite and investigation on solar light photocatalytic degradation of organic dyes

The Er3+:YAlO3/Fe-doped ZnO composite, a new photocatalyst which could effectively utilize visible light, was prepared. In succession, the Er3+:YAlO3/Fe-doped ZnO was characterized by XRD and SEM, respectively. Acid Red B dyes, was degraded under solar light irradiation to evaluate the photocatalytic activity of the Er3+:YAlO3/Fe-doped ZnO. In addition, the effects of Er3+:YAlO3 content, heat-treatment temperature and time on the photocatalytic activity of Er3+:YAlO3/Fe-doped ZnO were reviewed. Otherwise, the effect of initial dye concentration, Er3+:YAlO3/Fe-doped ZnO amount and solar light irradiation time on the photocatalytic degradation of Acid Red B were also investigated. It was found that the photocatalytic activity of Er3+:YAlO3/Fe-doped ZnO is much higher than that of Fe-doped ZnO and pure ZnO for the similar system. Perhaps, the use of the Er3+:YAlO3/Fe-doped ZnO may provide a new way to take advantage of ZnO in sewage treatment aspects using solar energy.

Preparation of nano-sized mixed crystal TiO2-coated Er3 + :YAlO3 by sol–gel method for photocatalytic degradation of organic dyes under visible light irradiation

In this work, an upconversion luminescence agent, crystallized Er(3 + ):YAlO(3), was synthesized and then coated by the nano-sized TiO(2) film through sol-gel technique. A novel TiO(2) photocatalyst, Er(3 + ):YAlO(3)/TiO(2), with high activity in visible light was subsequently prepared. The Er(3 + ):YAlO(3) and Er(3 + ):YAlO(3)/TiO(2) were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). The photocatalytic activity of Er(3 + ):YAlO(3)/TiO(2) photocatalyst was tested by the degradation of acid red B in aqueous solution as the primary model compound under visible light irradiation. The experimental results proved that the prepared TiO(2)-coated crystallized Er(3 + ):YAlO(3) was able to decompose the acid red B efficiently, and it is promising to use the idea to develop new TiO(2) photocatalyst with high activity for photocatalytic degradation under visible light.