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Title: The role of titanium-oxo clusters in the sulfate process for TiO2 production

Abstract

TiO2 is manufactured for white pigments, solar cells, self-cleaning surfaces and devices, and other photocatalytic applications. The industrial synthesis of TiO2 entails: (1) the dissolution of ilmenite ore (FeTiO3) in aqueous sulfuric acid which precipitates the Fe while retaining the Ti in solution, followed by (2) dilution or heating the Ti sulfate solution to precipitate the pure form of TiO2. The underlying chemistry of these processing steps remains poorly understood. Here we show that the dissolution of a simple TiIV-sulfate salt, representative of the industrial sulfate process for the production of TiO2, immediately self-assembles into a soluble Ti-octadecameric cluster, denoted as {Ti18}. We observed {Ti18} in solution by small-angle X-ray scattering and Ti extended X-ray absorption fine structure (Ti-EXAFS) analysis, and ultimately crystallized it for absolute identification. The {Ti18} metal-oxo cluster was previously reported as a polycation; but shown here, it can also be a polyanion, dependent on the number of sulfate ligands it carries. After immediate self-assembly, the {Ti18}-cluster persists until TiO2 precipitates, with no easily identified structural intermediates in the solution or solid state, despite the fact that the atomic arrangement of {Ti18} differs vastly from that of titania. The evolution from solution phase {Ti18} to precipitated TiO2more » nanoparticles was detailed by X-ray scattering and Ti-EXAFS. Here, we offer a hypothesis for the key mechanism of complete separation of Fe from Ti in the industrial sulfate process. These findings also highlight the emerging importance of the unusual Ti(Ti)5 pentagonal building unit, featured in {Ti18} as well as other early d0 transition metal-oxo clusters including Nb, Mo and W. Finally, this study presents an example of crystal growth mechanisms in which the observed “pre-nucleation cluster” does not necessarily predicate the structure of the precipitated solid.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Oregon State Univ., Corvallis, OR (United States)
Publication Date:
Research Org.:
Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
OSTI Identifier:
1547405
Alternate Identifier(s):
OSTI ID: 1530467
Grant/Contract Number:  
SC0010802
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Dalton Transactions
Additional Journal Information:
Journal Volume: 48; Journal Issue: 29; Journal ID: ISSN 1477-9226
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
ENGLISH
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Kozma, Karoly, Wang, Maoyu, Molina, Pedro I., Martin, Nicolas P., Feng, Zhenxing, and Nyman, May. The role of titanium-oxo clusters in the sulfate process for TiO2 production. United States: N. p., 2019. Web. doi:10.1039/c9dt01337g.
Kozma, Karoly, Wang, Maoyu, Molina, Pedro I., Martin, Nicolas P., Feng, Zhenxing, & Nyman, May. The role of titanium-oxo clusters in the sulfate process for TiO2 production. United States. https://doi.org/10.1039/c9dt01337g
Kozma, Karoly, Wang, Maoyu, Molina, Pedro I., Martin, Nicolas P., Feng, Zhenxing, and Nyman, May. 2019. "The role of titanium-oxo clusters in the sulfate process for TiO2 production". United States. https://doi.org/10.1039/c9dt01337g. https://www.osti.gov/servlets/purl/1547405.
@article{osti_1547405,
title = {The role of titanium-oxo clusters in the sulfate process for TiO2 production},
author = {Kozma, Karoly and Wang, Maoyu and Molina, Pedro I. and Martin, Nicolas P. and Feng, Zhenxing and Nyman, May},
abstractNote = {TiO2 is manufactured for white pigments, solar cells, self-cleaning surfaces and devices, and other photocatalytic applications. The industrial synthesis of TiO2 entails: (1) the dissolution of ilmenite ore (FeTiO3) in aqueous sulfuric acid which precipitates the Fe while retaining the Ti in solution, followed by (2) dilution or heating the Ti sulfate solution to precipitate the pure form of TiO2. The underlying chemistry of these processing steps remains poorly understood. Here we show that the dissolution of a simple TiIV-sulfate salt, representative of the industrial sulfate process for the production of TiO2, immediately self-assembles into a soluble Ti-octadecameric cluster, denoted as {Ti18}. We observed {Ti18} in solution by small-angle X-ray scattering and Ti extended X-ray absorption fine structure (Ti-EXAFS) analysis, and ultimately crystallized it for absolute identification. The {Ti18} metal-oxo cluster was previously reported as a polycation; but shown here, it can also be a polyanion, dependent on the number of sulfate ligands it carries. After immediate self-assembly, the {Ti18}-cluster persists until TiO2 precipitates, with no easily identified structural intermediates in the solution or solid state, despite the fact that the atomic arrangement of {Ti18} differs vastly from that of titania. The evolution from solution phase {Ti18} to precipitated TiO2 nanoparticles was detailed by X-ray scattering and Ti-EXAFS. Here, we offer a hypothesis for the key mechanism of complete separation of Fe from Ti in the industrial sulfate process. These findings also highlight the emerging importance of the unusual Ti(Ti)5 pentagonal building unit, featured in {Ti18} as well as other early d0 transition metal-oxo clusters including Nb, Mo and W. Finally, this study presents an example of crystal growth mechanisms in which the observed “pre-nucleation cluster” does not necessarily predicate the structure of the precipitated solid.},
doi = {10.1039/c9dt01337g},
url = {https://www.osti.gov/biblio/1547405}, journal = {Dalton Transactions},
issn = {1477-9226},
number = 29,
volume = 48,
place = {United States},
year = {Thu Jun 20 00:00:00 EDT 2019},
month = {Thu Jun 20 00:00:00 EDT 2019}
}

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Cited by: 12 works
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Works referenced in this record:

Particle Size, Shape and Activity for Photocatalysis on Titania Anatase Nanoparticles in Aqueous Surroundings
journal, October 2011


The Role of Bi 3+ in Promoting and Stabilizing Iron Oxo Clusters in Strong Acid
journal, April 2018


The crystal structure of zirconyl chloride octahydrate and zirconyl bromide octahydrate
journal, July 1956


Electrochemical Photolysis of Water at a Semiconductor Electrode
journal, July 1972


Amphoteric Aqueous Hafnium Cluster Chemistry
journal, April 2016


Structure of the Complex Ion in Aqueous Solutions of Zirconyl and Hafnyl Oxyhalides
journal, July 1960


Characterization of Chemical Speciation of Titanyl Sulfate Solutions for Production of Titanium Dioxide Precipitates
journal, March 2009


Giant metal-oxide-based spheres and their topology: from pentagonal building blocks to keplerates and unusual spin systems
journal, November 2001


Aqueous formation and manipulation of the iron-oxo Keggin ion
journal, February 2015


Aqueous Hafnium Sulfate Chemistry: Structures of Crystalline Precipitates
journal, September 2014


Crystal structure of a complex basic zirconium sulfate
journal, December 1987


Small Titanium Oxo Clusters: Primary Structures of Titanium(IV) in Water
journal, March 2016


Titanium-Oxide Host Clusters with Exchangeable Guests
journal, December 2017


Titanium Dioxide-Based Nanomaterials for Photocatalytic Fuel Generations
journal, May 2014


Counteranion-Stabilized Titanium(IV) Isopolyoxocationic Clusters Isolated from Water
journal, April 2016


Structural absorption by barbule microstructures of super black bird of paradise feathers
journal, January 2018


Sol–gel reactions of titanium alkoxides and water: influence of pH and alkoxy group on cluster formation and properties of the resulting products
journal, December 2009


Hafnium Sulfate Prenucleation Clusters and the Hf 18 Polyoxometalate Red Herring
journal, March 2014


U(IV) Aqueous Speciation from the Monomer to UO 2 Nanoparticles: Two Levels of Control from Zwitterionic Glycine Ligands
journal, May 2017


Aqueous Bismuth Titanium-Oxo Sulfate Cluster Speciation and Crystallization
journal, November 2017


A literature review of titanium metallurgical processes
journal, July 2011


Water-Soluble Pentagonal-Prismatic Titanium-Oxo Clusters
journal, August 2016


Theoretical Studies on Anatase and Less Common TiO 2 Phases: Bulk, Surfaces, and Nanomaterials
journal, May 2014


On the Crystal Structure of Some Basic Aluminium Salts.
journal, January 1960


Hydrated Titanium Oxide. Thermal Precipitation from Titanium Sulfate Solutions.
journal, March 1933


Mini review on photocatalysis of titanium dioxide nanoparticles and their solar applications
journal, September 2013


Review of functional titanium oxides. I: TiO2 and its modifications
journal, September 2016


A comprehensive comparison of transition-metal and actinyl polyoxometalates
journal, January 2012


Large Aqueous Aluminum Hydroxide Molecules
journal, January 2006


Water-soluble titanium-oxides: Complexes, clusters and nanocrystals
journal, March 2019


Atomic-scale cation dynamics in a monolayer VO X /α-Fe 2 O 3 catalyst
journal, January 2015


Structural Characterization of Modular Supramolecular Architectures in Solution
journal, November 2004


Identification of Ti Clusters during Nucleation and Growth of Sol—Gel-Derived TiO 2 Nanoparticles
journal, August 2013


Structures of Hydrated Titanium and Vanadium Ions in Aqueous Solutions Studied by X-Ray Absorption Spectroscopy
journal, November 1990


Understanding TiO 2 Photocatalysis: Mechanisms and Materials
journal, May 2014


The Construction of High-Nuclearity Isopolyoxoniobates with Pentagonal Building Blocks: [HNb27O76]16− and [H10Nb31O93(CO3)]23−
journal, November 2009


Unprecedented and Differently Applicable Pentagonal Units in a Dynamic Library: A Keplerate of the Type {(W)W 5 } 12 {Mo 2 } 30
journal, November 2008


Fullerene-like Polyoxotitanium Cage with High Solution Stability
journal, February 2016


Size tailoring of TiO2 anatase nanoparticles in aqueous medium and synthesis of nanocomposites. Characterization by Raman spectroscopy
journal, February 2003


Probing protein fine structures by wide angle solution X-ray scattering
journal, June 2000


Titanate and titania nanostructured materials for environmental and energy applications: a review
journal, January 2015


TiO 2 Photocatalysis: A Historical Overview and Future Prospects
journal, December 2005


Isomerism in Titanium-Oxo Clusters: Molecular Anatase Model with Atomic Structure and Improved Photocatalytic Activity
journal, December 2018


The Construction of High-Nuclearity Isopolyoxoniobates with Pentagonal Building Blocks: [HNb27O76]16− and [H10Nb31O93(CO3)]23−
journal, November 2009


Amphoteric Aqueous Hafnium Cluster Chemistry
journal, April 2016


Aqueous Bismuth Titanium-Oxo Sulfate Cluster Speciation and Crystallization
journal, November 2017


Large Aqueous Aluminum Hydroxide Molecules
journal, March 2006


Works referencing / citing this record:

Metal Organic Framework Derivative Improving Lithium Metal Anode Cycling
journal, January 2020


Effects of organic ammonium cations on the isolation of {Ti 4 } cyclic clusters from water: an 17 O NMR study
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