Search query: "BiOCl" and "BI2O3"

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abstract: Abstract For the first time we report novel BiOCl/Bi2O3 photocatalyst functional under visible light irradiation. Even though both the individual BiOCl and Bi2O3 show very low photocatalytic efficiency under visible light irradiation, their heterojunctions provide unexpectedly high efficiency in decomposing organic compounds. Furthermore, the BiOCl/Bi2O3 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 CO2 from gaseous 2 propanol (IP) and 10.5 times of efficiency in removing aqueous 1,4 terephthalic acid (TA) under visible light l 420 nm irradiation. In this BiOCl/Bi2O3 system the BiOCl seems to work as main photocatalyst, while the role of Bi2O3 is a sensitizer absorbing visible light. The photocatalytic mechanism has been proposed based on the relative band position of these two semiconductors.
author_names: Seung Yong Chai

Yong Joo Kim

M H Jung

Ashok Kumar Chakraborty

Dongwoon Jung

Wan In Lee
title: Heterojunctioned BiOCl/Bi2O3, a new visible light photocatalyst
year: 2009

abstract: The paper reviews solid catalyzed oxidation and reduction processes for the treatment of wastewater that contains small concentrations of toxic compounds and for which separation is not economical while biological treatment is not feasible. Specifically, the objectives are (1) to understand the interactions between catalytic materials and various pollutants, (2) to provide a database for catalyst selection, and (3) to assess the potential of these processes for commercialization. The review suggests the following well investigated solutions: (1) Supported metal (Ru/CeO2, Pt/CeO2, and Ru/C) and metal oxides (CuO ZnO CoO, MnO2/CeO2, CoO/Bi2O3, and V2O5/Al2O3) are the most promising catalysts for the destruction of refractory organic compounds with nearly 100% selectivity to CO2; (2) CoO/CeO2 and MnO2/CeO2 are the most active catalysts for ammonia oxidation at temperatures of 263 400 degC; (3) activated carbon, preferably in the presence of copper ions, is an active catalyst for the oxidation of cyanides and
author_names: Yurii I Matatov-Meytal and

Moshe Sheintuch
title: Catalytic Abatement of Water Pollutants
year: 1998

abstract: A Bi2O3 nanoparticle modified BiOCl composite was synthesized by a solvothermal method combined with in situ reduction and oxidation in KBH4 and H2O2 solutions respectively. The thickness of a BiOCl nanosheet and the amount of Bi2O3 nanoparticle can be adjusted by changing the KBH4 concentration. The structure, morphology, elemental composition and optical absorption performance were characterized by using an X ray diffraction diffractometer, a scanning electron microscope, a high resolution transmission electron microscope, an X ray photoelectron spectroscope and a UV Vis diffuse reflection spectroscope respectively. A nanolayered hierarchical structure of BiOCl was observed, and Bi2O3 nanoparticles were found to be evenly distributed on the surface/interface of the nanosheets. The photocatalytic activity of the composite was tested by the degradation of 40 mg L( 1) methyl orange solution under UV light illumination. The Bi2O3/BiOCl composite prepared in a KBH4 concentration of 0.02 M achieved the highest photocatalytic rate of 95.7% in 8 min under UV light illumination with a kinetic constant of 0.3125 l min( 1) The photocatalytic mechanism of the composite has been discussed.
author_names: Jiajia Hu

Guangqing Xu

Jinwen Wang

Jun Lv

Xinyi Zhang

Ting Xie

Zhi-xiang Zheng

Yucheng Wu
title: Photocatalytic property of a Bi2O3 nanoparticle modified BiOCl composite with a nanolayered hierarchical structure synthesized by in situ reactions.
venue: Dalton transactions
year: 2015

abstract: This work is devoted to the preparation of carbon supported bismuth palladium catalysts for the selective oxidation of glucose to gluconic acid, and to the understanding of the promoting role played by Bi in these catalysts. Catalysts were prepared according to various experimental procedures from two kinds of precursors, containing either classical inorganic ligands (chloride, nitrate) or organic ligands of the carboxylate type: the acetates and derivatives of the pyrazine 2,3 dicarboxylic acid. Depending on the precursors used, the catalytic performances were found to be very different; catalysts prepared by deposition of acetate type precursors display the highest activity. The incorporation of bismuth in the Pd/C catalysts was confirmed to increase drastically the catalytic activity. The catalysts were characterized before and after their use in the catalytic operation by XRD, XPS, BET and IR. Depending on the preparation procedure used, the presence of BiOCl, Bi2O3 and several Bi Pd alloys in the bimetallic catalysts after the activation step was deduced from XRD studies. Partial dissolution of bismuth during the catalytic tests was demonstrated by atomic absorption analysis of the reaction medium and elaborate investigations were undertaken to understand the individual effects of the various constituents of the reaction mixture on the dissolution process. Monometallic Bi/C catalysts were found to lose significantly larger amounts of bismuth than bimetallic Pd Bi/C catalysts. Both glucose and gluconate appear as responsible for the dissolution of the promoting element. Notwithstanding the increase in the conversion rate observed when two monometallic Pd/C and Bi/C catalysts were used simultaneously, it was shown that the promoting role of bismuth was not merely dictated by the presence of bismuth in solution.
author_names: Mireille Wenkin

Roland Touillaux

Patricio Ruiz

Bernard Delmon

Michel Devillers
title: Influence of metallic precursors on the properties of carbon supported bismuth promoted palladium catalysts for the selective oxidation of glucose to gluconic acid
year: 1996

abstract: alpha Bi2O3 is the thermodynamically stable phase of Bi2O3 at room temperature. We have performed a theoretical and experimental investigation of its electronic structure using a combination of gradient corrected density functional theory (DFT) along with x ray photoemission and O K shell x ray absorption and emission spectroscopies. We examine the nature of bonding in alpha Bi2O3 and in particular explore the nature of the stereochemically active Bi electron lone pair. The Bi 6s states are found to be concentrated at the bottom of the valence band but the states contributing to the lone pair on Bi are derived from the top of the valence band. Mixing between O 2p and Bi 6s states is found to be crucial in producing the asymmetric density on Bi. The role of the lone pair in the fast ion conductor delta Bi2O3 is also investigated, through calculation of the electronic structure with and alignment of oxygen vacancies. Alignment of the vacancies along results in the most energetically favorable configuration of the delta phase, contrary to previous force field calculations and electrostatic arguments which favor the alignment.
author_names: Aron Walsh

Graeme W Watson

David J Payne

Russell G Edgell

Jinghua Guo

Per Anders Glans

Timothy Learmonth

Kevin E Smith
title: Electronic structure of the alpha and delta phases of Bi2O3: A combined ab initio and x ray spectroscopy study
year: 2006

abstract: Abstract Although Bi based compounds are effective photocatalysts for degrading organic pollutants under visible light irradiation, their visible light photocatalytic activities are still low and far from practical application. In this study, novel graphene functionalized Bi bridge Z scheme black BiOCl/Bi2O3 (black BiOCl Bi Bi2O3/rGO) heterojunctions with oxygen vacancies were prepared via in situ Fe reduction of BiOCl/graphene oxide nanoplates. In comparison with BiOCl/graphene oxide nanoplates, the black BiOCl Bi Bi2O3/rGO heterojunctions have stronger visible light absorption, and exhibit more efficient charge separation and higher visible light photocatalytic activity in degrading 2 nitrophenol (2NP) The black BiOCl Bi Bi2O3/rGO0.4 shows the highest visible light photocatalytic activity with almost complete degradation of 2NP, which is attributed to proper bandgap match between black BiOCl and Bi2O3, multiple charge transfer channels via Bi bridge and rGO, and efficient charge separation. Of special importance, black BiOCl Bi Bi2O3/rGO heterojunction can effectively treat real industrial wastewater with 70.3% COD removal efficiency, and it shows superior long term stability. Additionally, a possible photocatalytic mechanism of black BiOCl Bi Bi2O3/rGO heterojunctions based on multiple charge transfer channels was proposed.
author_names: Fang Deng

Qian Zhang

Lixia Yang

Xubiao Luo

Aijie Wang

Shenglian Luo

Dionysios D Dionysiou
title: Visible light responsive graphene functionalized Bi bridge Z scheme black BiOCl/Bi2O3 heterojunction with oxygen vacancy and multiple charge transfer channels for efficient photocatalytic degradation of 2 nitrophenol and industrial wastewater treatment
year: 2018

abstract: In this work, we have developed 3D hybrid microstructures consisting of a short ferromagnetic CoNi segment for wireless magnetic control, coupled to a photocatalytic Bi2O3/BiOCl segment for water remediation under UV visible light. These hybrid microstructures (pillars and helices) were fabricated using 3D photolithography and template assisted electrodeposition, followed by in situ creation of a Bi2O3/BiOCl heterojunction after oxidation of Bi. This heterojunction is not only active under a wider solar spectrum but also ensures sufficient charge separation and hence low electron hole recombination rate. As a result, these hybrid microstructures were able to degrade rhodamine B dye with a 90% efficiency in 6 hours. On application of magnetic fields we were able to precisely control the structures and collect them for reuse. Cytotoxicity tests were performed on our hybrid structures and a 95% cell viability was reported showing that our structures are biocompatible.
author_names: Fajer Mushtaq

Miguel Guerrero

Mahmut Selman Sakar

Marcus Hoop

Andre Machado Lindo

Jordi Sort

Xiang-Zhong Chen

Bradley J Nelson

Eva Pellicer

Salvador Pane
title: Magnetically driven Bi2O3/BiOCl based hybrid microrobots for photocatalytic water remediation
year: 2015

abstract: Hydrous bismuth oxides (HBOs) have been investigated as a possible adsorbent for fluoride removal from water. Apart from bismuth trioxide (Bi2O3) compound, three additional HBOs, named as HBO1, HBO2, and HBO3 were synthesized in the laboratory and examined for their relative potentials for fluoride removal from aqueous solutions. HBO1 was observed to have highest fluoride removal at 10mg/L initial concentration in aqueous environment. Among competitive anions, sulfate and chloride affect the fluoride removal by HBO1 more adversely than bicarbonate. Characterization of HBOs using X ray diffraction (XRD) pattern analyses indicated crystalline structures, and the broad chemical composition of materials showed successive increase of Bi(OH)3 from HBO1 to HBO3, with decrease of BiOCl in the same order. Fourier Transform Infrared (FTIR) spectroscopy analyses indicated presence of Bi O bond and successively increasing number of peaks corresponding to OH ion from HBO1 to HBO3. Scanning Electron Microscopic (SEM) images of HBOs show rough and porous structure of the materials. Presence of higher proportion of chloride compound in HBO1 with respect to others appears to be the factor responsible for its better performance in fluoride removal from aqueous solutions.
author_names: Arun Lal Srivastav

Prabhat K Singh

Varsha Srivastava

Yogesh Chandra Sharma
title: Application of a new adsorbent for fluoride removal from aqueous solutions.
venue: Journal of hazardous materials
year: 2013

abstract: The encapsulation of bismuth as BiOCl/Bi2O3 within ultra short (ca. 50 nm) single walled carbon nanocapsules (US tubes) has been achieved. The Bi@US tubes have been characterized by high resolution transmission electron microscopy (HR TEM) energy dispersive X ray spectroscopy (EDS) thermogravimetric analysis (TGA) X ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Bi@US tubes have been used for intracellular labeling of pig bone marrow derived mesenchymal stem cells (MSCs) to show high X ray contrast in computed tomography (CT) cellular imaging for the first time. The relatively high contrast is achieved with low bismuth loading (2.66% by weight) within the US tubes and without compromising cell viability. X ray CT imaging of Bi@US tubes labeled MSCs showed a nearly two fold increase in contrast enhancement when compared to unlabeled MSCs in a 100 kV CT clinical scanner. The CT signal enhancement from the Bi@US tubes is 500 times greater than polymer coated Bi2S3 nanoparticles and several fold that of any clinical iodinated contrast agent (CA) at the same concentration. Our findings suggest that the Bi@US tubes can be used as a potential new class of X ray CT agent for stem cell labeling and possibly in vivo tracking.
author_names: Eladio J Rivera

Lesa A Tran

Mayra Hernandez-Rivera

Diana M Yoon

Antonios G Mikos

Irene A Rusakova

Benjamin Y Cheong

Maria da Graca Cabreira-Hansen

James T Willerson

Emerson C Perin

Lon J Wilson
title: Bismuth@US tubes as a Potential Contrast Agent for X ray Imaging Applications.
venue: Journal of materials chemistry. B
year: 2013

abstract: The title material is prepared by solid state reaction of a stoichiometric mixture of Bi2O3, BiOCl, and Nb2O5 (evacuated silica tube, 1173 K, 20 h) and characterized by powder XRD and UV/VIS diffuse reflectance spectroscopy.
author_names: Hironori Fujito

Hironobu Kunioku

Daichi Kato

Hajime Suzuki

Masanobu Higashi

Hiroshi Kageyama

Ryu Abe
title: Layered Perovskite Oxychloride Bi4NbO8Cl: A Stable Visible Light Responsive Photocatalyst for Water Splitting.
year: 2016