Synthesis, characterization, photocatalytic activity of visible-light-responsive photocatalysts BiOxCly/BiOmBrn by controlled hydrothermal method (original) (raw)
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New efficient visible light photocatalyst based on heterojunction of BiOCl–bismuth oxyhydrate
Applied Catalysis A: General, 2012
A novel active photocatalyst, which is a heteroconjuction of a bismuth oxyhydrate and BiOCl, has been synthesized by a simple hydrothermal method. The photocatalytic activity of the new material was measured in the degradation of Rhodamine B (RhB) and Acetophenone (AP) and in the photocatalytic oxidation of iodide in water under UV-vis and visible light irradiations respectively. The heterojunction between bismuth oxyhydrate and BiOCl provided exceptional photocatalytic activity, whereas both the individual bismuth oxyhydrate and BiOCl showed a negligible efficiency. Compared to Degussa P25, the new composite material demonstrated 5 times higher activity in removing aqueous RhB under visible light ( ≥ 420 nm) irradiation. The chemical composition and crystal structure were investigated using powder X-ray diffraction, scanning and transmission electron microscopy, and thermal methods. The preliminary study has revealed the bismuth oxyhydrate has tetragonal crystal structure with unit cell parameters a = b = 5.674Å, c = 10.353Å, unit cell volume V = 333.3Å 3 and possible P4/mmm (No. 123) space group. Temperature behavior of new photocatalyst has been investigated. It was found that at heating to 550 • C for 45 min the new phase transforms into well-known monoclinic Bi 2 O 3 .
Frontiers in Chemistry
An important target of photoelectrocatalysis (PEC) technology is the development of semiconductor-based photoelectrodes capable of absorbing solar energy (visible light) and promoting oxidation and reduction reactions. Bismuth oxyhalide-based materials BiOX (X = Cl, Br, and I) meet these requirements. Their crystalline structure, optical and electronic properties, and photocatalytic activity under visible light mean that these materials can be coupled to other semiconductors to develop novel heterostructures for photoelectrochemical degradation systems. This review provides a general overview of controlled BiOX powder synthesis methods, and discusses the optical and structural features of BiOX-based materials, focusing on heterojunction photoanodes. In addition, it summarizes the most recent applications in this field, particularly photoelectrochemical performance, experimental conditions and degradation efficiencies reported for some organic pollutants (e.g., pharmaceuticals, organ...
New metastable bismuth oxide-BiOCl heterojunction: efficient visible light photocatalyst
Applied Catalysis A General
A novel active photocatalyst, which is a heteroconjuction of a bismuth oxyhydrate and BiOCl, has been synthesized by a simple hydrothermal method. The photocatalytic activity of the new material was measured in the degradation of Rhodamine B (RhB) and Acetophenone (AP) and in the photocatalytic oxidation of iodide in water under UV-vis and visible light irradiations respectively. The heterojunction between bismuth oxyhydrate and BiOCl provided exceptional photocatalytic activity, whereas both the individual bismuth oxyhydrate and BiOCl showed a negligible efficiency. Compared to Degussa P25, the new composite material demonstrated 5 times higher activity in removing aqueous RhB under visible light ( ≥ 420 nm) irradiation. The chemical composition and crystal structure were investigated using powder X-ray diffraction, scanning and transmission electron microscopy, and thermal methods. The preliminary study has revealed the bismuth oxyhydrate has tetragonal crystal structure with unit cell parameters a = b = 5.674Å, c = 10.353Å, unit cell volume V = 333.3Å 3 and possible P4/mmm (No. 123) space group. Temperature behavior of new photocatalyst has been investigated. It was found that at heating to 550 • C for 45 min the new phase transforms into well-known monoclinic Bi 2 O 3 .
The Journal of Physical Chemistry C, 2012
In this study, a facile and effective method to modify the photocatalytic performance of a bismuth oxybromide (BiOBr) semiconductor through the fabrication of a heterojunction with a hydrated bismuth oxide (BHO) is reported. The new yBiOBr-(1 − y)BHO heterojunction, synthesized by a simple hydrothermal method, exhibits a high photocatalytic activity under visible light irradiation for the photodegradation of typical organic pollutants in water, such as Rhodamine B (RhB) and acetophenone (AP). Both the individual BiOBr and BHO components show very low photocatalytic efficiency. Furthermore, the unique photocatalytic performance of the new hybrid material was demonstrated through the uphill photocatalytic reaction that involves the oxidation of potassium iodide (KI) to triiodide. The remarkable photocatalytic activity of the coupled system is directly related to the effectual charge carrier separation due to the formation of the heterostructure. 0.9BiOBr-0.1BHO shows a higher photocatalytic activity as compared with other members of the same family, 0.8BiOCl-0.2BHO and 0.8BiOI-0.2BHO, which is directly ascribed to a synergistic effect of the energy bandgap structure and flow of charge carriers through the heterojunction, surface area, and light absorbance. In comparison with TiO 2 (Degussa P25), the new composite material demonstrated 10.7 times higher activity in removing aqueous RhB under visible light (λ ≥ 420 nm) irradiation. Study of the photocatalytic mechanism proves that the degradation of RhB under visible light irradiation over the as-prepared 0.9BiOBr-0.1BHO is mainly via a direct hole oxidation mechanism and superoxide oxidation pathways. The resulting yBiOBr-(1 − y)BHO composites exhibit high photocatalytic and thermal stabilities and are very promising photocatalysts for degradation of organic pollutants in water and for other applications.
Cogent Chemistry, 2015
BiOCl, BiOBr, and BiOI have been synthesized by wet chemical route using bismuth nitrate (Bi(NO3)3.5H2O) and potassium halides, KCl, KBr, and KI, using a mixture of de-ionized water and ethanol as the solvent. Synthesized samples were characterized by X-ray diffraction and high-resolution SEM to observe the crystalline phase and crystallite size. Effective surface areas of the synthesized samples were estimated by Brunauer-Emmett-Teller studies. Photoactive properties of these samples were studied under three types of light exposure conditions viz. UV light from mercury vapour lamp, natural sunlight, and visible radiations from a 100-W incandescent tungsten filament. Degradation of methyl orange (MO) in aqueous media was estimated spectrophotometerically in visible range from the area under the curve with a peak at 464 nm. Kinetic constant for degradation reaction was calculated assuming the pseudo-first-order degradation mechanism. It was revealed that all the three samples show excellent degradation of MO in UV exposure with BiOCl as the most efficient photocatalyst in these radiations. BiOBr shows highest photodegradation performance among the three samples under natural sunlight exposure. Overall performance of the three photocatalyst samples is much better than the popular titanium dioxide photocatalyst.
3RD INTERNATIONAL CONFERENCE ON CONDENSED MATTER AND APPLIED PHYSICS (ICC-2019)
The pure Bismuth Oxyhalides [BiOX (X = Cl, Br and I)] nano-crystals can be used as efficient photo-catalysts for the purpose of water purification under visible light irradiations. BiOX materials can efficiently degrade different types of toxic chemicals emitted from textile, pharmaceutical and pesticide industries thereby acting as effective materials for waste water remediation. In this work, BiOX materials have been synthesized using Bi2O3 as the precursor following a facile chemical route. The as-synthesized samples have been characterized by X-ray diffraction (XRD), UV-Vis Diffused Reflectance Spectroscopy (UV-Vis DRS), Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM) and Photoluminescence Spectroscopy (PL). Finally, the BiOX samples have been utilized for degradation of harmful, xanthene, textile dye like Rhodamine B (RhB). It has been observed that the synthesized materials were capable to degrade RhB dye within just 120 min under visible light irradiation exhibiting excellent photocatalytic activity which in turn helped to establish BiOX materials as a potential photo-catalyst to combat environmental water pollution.
A Review on BiOX (X= Cl, Br and I) Nano-/Microstructures for Their Photocatalytic Applications
Journal of nanoscience and nanotechnology, 2019
In the recent past, bismuth oxyhalides (BiOX) have been widely used for the photocatalytic degradation of the organic pollutants and other environmental remediation because of their higher stability, economic viability, nontoxicity and effective charge separation. We begin with the review of the different approaches adopted so far for BiOX (X = Cl, Br, and I) synthesis and a study of their photocatalytic performances under UV and visible light towards the various organic as well as inorganic pollutants. Later on, a study on further enhancement of the efficiency of BiOX under UV and visible light irradiation using recent advancements would be presented. The new approaches involve controlled morphology by forming composite and hybrid materials with other semiconductors and also doping with other metals and nonmetals that would undoubtedly be beneficial in the interfacial charge transfer and efficient inhibition of the photo-generated species. Herein, we would also exploit the recent d...
Heterojunctioned BiOCl/Bi2O3, a new visible light photocatalyst
Journal of Catalysis, 2009
For the first time we report novel BiOCl/Bi 2 O 3 photocatalyst functional under visible light irradiation. Even though both the individual BiOCl and Bi 2 O 3 show very low photocatalytic efficiency under visible light irradiation, their heterojunctions provide unexpectedly high efficiency in decomposing organic compounds. Furthermore, the BiOCl/Bi 2 O 3 can induce complete mineralization without formation of intermediate species by utilizing the holes generated in the VB of BiOCl. Compared to the Degussa P25, it demonstrates 5.7 times of efficiency in evolving CO 2 from gaseous 2-propanol (IP), and 10.5 times of efficiency in removing aqueous 1,4-terephthalic acid (TA) under visible light (λ 420 nm) irradiation. In this BiOCl/Bi 2 O 3 system the BiOCl seems to work as main photocatalyst, while the role of Bi 2 O 3 is a sensitizer absorbing visible light. The photocatalytic mechanism has been proposed based on the relative band position of these two semiconductors.
Journal of Colloid and Interface Science, 2019
BiO x Cl y /BiO m Br n /BiO p I q GO 2-hydroxybenzoic acid Photocatalytic Composites a b s t r a c t Herein, the preparation of numerous bismuth oxychloride/bismuth oxybromide/bismuth oxyiodide/ graphene oxide (BiO x Cl y /BiO m Br n /BiO p I q /GO) composites is reported. A facile hydrothermal method was employed to synthesize these photocatalysts, which had various GO contents. A total of 10 bismuth-oxyhalide composites were isolated and characterized using FE-SEM, XRD, FE-TEM, UV-Vis-DRS, FT-IR, EPR, HR-XPS, PL, and BET. The photocatalytic efficiencies of these 10 bismuth-oxyhalide composites were measured under visible-light irradiation by estimating the concentration of 2-hydroxybenzoic acid (HBA) degradation. The findings indicated that the rate constant order of the HBA degradations was BiOCl/BiOBr/BiOI/GO