Bismuth Oxyhalide-Based Materials (BiOX: X = Cl, Br, I) and Their Application in Photoelectrocatalytic Degradation of Organic Pollutants in Water: A Review (original) (raw)
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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.
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.
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...
Korean Journal of Chemical Engineering, 2018
The main environmental problems associated with water body pollution are typically those caused by the discharge of untreated effluents released by various industries. Wastewater from the textile dye industry is itself a large contributor and contains a huge number of complex components, a wide spectrum of organic pollutants with high concentration of biochemical oxygen demand (BOD)/chemical oxygen demand (COD) and other toxic elements. One of several potential techniques to degrade such reactive dyes before being discharged to water bodies is photocatalysis, and bismuth-based photocatalysts are rapidly gaining popularity in this direction. Bismuth oxyhalides, BiOX (X=Cl, Br, I, F), as a group of ternary compound semiconductors (V-VI-VII), have been explored extensively for their photocatalytic activity due to their unique crystal lattice with special layered structure in pure as well as modified form. With suitable band gap and band edge positions, which are a required condition for efficient water breakup and high photon absorption, BiOCl scores over other oxyhalides. Photocatalytic activity depends on many factors such as synthesis method, morphology, size, illumination type, dye choice among others. This paper gives a critical review on bismuth oxyhalides as a family on various aspects of modifications such as doping (with unique and interesting metals as well), morphology and synthesis parameters, polymer and carbon assisted composites in order to further enhance the photocatalytic efficiency in UV/visible region of solar spectrum.
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 .
ACS Omega
Herein, we demonstrate the fabrication of Bi(0)-doped bismuth oxyhalide solid solution films for the removal of trace organic pollutants (TrOPs) in water. With the advantage of a viscous AlOOH sol, very high loadings (75 wt %) of bismuth oxyhalides were embedded within the thin films and calcined at 500°C to develop porous alumina composite coatings. Various concentrations of Bi(0) doping were tested for their photocatalytic activity. Seven TrOPs including iopromide (IPRM), iohexol (IHX), iopamidol (IPMD), sulfamethoxazole (SMX), carbamazepine, venlafaxine, and bezafibrate (BZF) were selected for this study based on their occurrence and detection in effluents and surface waters worldwide. In all tests, with the exception of IPRM, 3% Bi(0)-doped BiOCl 0.875 Br 0.125 showed highest activity, which can be attributed to its unique, highly organized, and compact morphology besides its well-matched energy band positions. Although IPMD, IHX, IPRM, and SMX are susceptible to photolysis, still the photocatalytic activity significantly augmented the removal of all tested compounds. In addition, analysis of the surface charge excluded electrostatic interactions and confirmed the ion-exchange adsorption mechanism for the high degradation rate of BZF in the presence of bismuth oxyhalides.
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 .
Journal of Molecular Catalysis A: Chemical, 2014
Bismuth oxyhalide and its composite belong to a new family of visible light driven photocatalysts and attract more and more attention because of their interesting structures dependent on the photocatalytic performance arisen from their layered structures interleaved with [Bi 2 O 2 ] slabs and double halogen atoms slabs. An effective and simple strategy to improve the photocatalytic activity of a photocatalyst is the construction of a heterostructure, as the heterojunction has great potential in tuning the desired electronic properties of the composite photocatalysts and efficiently separating the photogenerated electron-hole pairs. This is the first report that a series of BiO x Cl y /BiO m Br n heterojunctions are prepared using controlled hydrothermal methods. The compositions and morphologies of BiO x Cl y /BiO m Br n could be controlled by adjusting some growth parameters, including reaction pH, time, and temperature. The products are characterized by XRD, SEM-EDS, HR-TEM, DR-UV, BET, CL, and HR-XPS.
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.
Journal of Colloid and Interface Science, 2019
In the recent past, due to the excellent optical properties and synergistic effect, bismuth oxyhalides based composites have gained significant attention in the field of photocatalysis. Herein, we demonstrate a green Azadirachta indica (Neem) (A.I.) leaf extract assisted hydrolysis method for the synthesis of green G-BiOBrxI1-x photocatalysts. The phytochemicals rich contents of the leaf extract demonstrated natural stabilizing properties, which effectively controlled the size of the composites and ultimately enhanced the specific surface area and porosity of the samples. Meanwhile, the leaf extract also proved to be an excellent sensitizer for the composites that boosted the optical window of the G-BiOBrxI1-x photocatalysts for high level of solar energy harvesting. The as-prepared G-BiOBrxI1-x photocatalysts possessed three dimensional nanoplates like structure with successive modulation of the band gaps from 2.28 eV to 1.98 eV by varying the Br/I ratio. Furthermore, the photocatalytic activity of the as-prepared G-BiOBrxI1-x samples were measured and compared with C-BiOBr0.5I0.5 synthesized by hydrolysis route without the leaf extract. The G-BiOBrxI1-x photocatalysts exhibited much improved photocatalytic performance than C-BiOBr0.5I0.5 for methyl orange (MO) and amoxicillin (AMX) degradation under visible light irradiation. In particular G-BiOBr0.2I0.8 exhibited the highest photocatalytic brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by SZTE Publicatio Repozitórium-SZTE-Repository of Publications activity, which was mainly attributed to the electron accepting π-conjugated system offered by the complex structural constituents of the leaf extract, thereby facilitating the charge transfer process and efficient separation of photogenerated electron-hole pairs. Furthermore, the high stability of BiOBr0.2I0.8 was demonstrated by the recyclability experiment, which offers promising opportunities for its practical application as a photocatalyst.