Content
Preface
Purpose and target audience
Research and Application Significance of High-Purity Nano-Tungsten Oxide
Book Structure and Usage Guide
Abbreviations and symbols
Commonly used abbreviations (such as WO₂.₉ , BTO, APT)
Physical and chemical symbols and units
Chapter 1 Introduction
1.1 History And Discovery Of High-Purity Nano-Tungsten Oxide
1.2 Classification Of Non-Stoichiometric Tungsten Oxide
WO₃ , WO₂.₉ , WO₂.₇₂ , WO₂
1.3 The Status Of High-Purity Nano-Tungsten Oxide In The Tungsten Industry Chain
1.4 Current Status And Trends Of Research And Application
1.5 Scope And Objectives Of This Book
Chapter 2 Basic Properties of High-Purity Nano-Tungsten Oxide
2.1 Chemical Composition And Non-Stoichiometric Properties
2.1.1 Chemical Formula And Oxygen-Tungsten Ratio
WO₂.₉ and oxygen content range (19.0-19.5 wt%)
Comparison with WO₃ , WO₂.₇₂ , WO₂
2.1.2 Formation Mechanism Of Non-Stoichiometric Ratio
Generation and stability of oxygen vacancies
Effects of Stoichiometric Deviations on Performance
2.1.3 Impurities And Purity Control
Common impurities (Fe, Mo, Si) sources
2.2 Crystal Structure And Oxygen Defect Mechanism
2.2.1 Crystal Structure Type
Structural characteristics of the monoclinic phase (P2₁ /n)
Structural differences from WO₃
2.2.2 Microscopic Distribution Of Oxygen Vacancies
Types of point defects and surface defects
Calculation of oxygen vacancy density (10¹⁹ -10²¹ cm⁻³ )
2.2.3 Structural Characterization Methods
Characteristic peak analysis of XRD and Raman spectra
Relationship between lattice parameters and defects
2.2.4 Thermal Stability And Phase Change
Effect of temperature on crystal structure (stable at <600°C)
Phase transitions during oxidation and reduction
2.3 Physical Properties
2.3.1 Band Gap Energy
Bandgap range of WO₂.₉ (2.4-2.8 eV)
Regulation mechanism of oxygen defects on band gap
Characteristic absorption of UV-Vis spectra
2.3.2 Specific Surface Area And Particle Size
m² /g) of micron-scale (10-50 μm) and nanoscale (50-100 nm)
Effect of Particle Size Distribution on Performance
2.3.3 Morphological Characteristics
Common morphologies (nanoparticles, nanorods, thin films)
Thermodynamics and kinetics of morphology formation
2.3.4 Optical Properties
Cause of color (dark blue)
Light absorption and reflection properties
2.3.5 Thermal And Mechanical Properties
Thermal conductivity and thermal expansion coefficient
Mechanical strength of nanostructures
2.4 Chemical Properties
2.4.1 Oxidation State And Reactivity
Mixed oxidation states of W⁵⁺ / W⁶⁺
Reactivity with O₂ and H₂
2.4.2 Surface Chemistry And Active Sites
Catalytic effect of surface oxygen defects
Adsorption performance (H₂O , CO₂ , NO₂ )
2.4.3 Conductivity And Electrochemical Properties
Conductivity range (10⁻³ -10⁻² S/cm)
Electron transfer in electrochemical reactions
2.4.4 Corrosion Resistance And Stability
Stability in acid and alkaline environments
Oxidation risk during long-term storage
2.5 Nano-Effects On Performance
2.5.1 Physical Basis Of Size Effect
Quantum confinement and surface effects
Bandgap regulation by nanometer size
2.5.2 Performance Enhancement Mechanism
Improved photocatalytic efficiency (>400 μmol·g⁻¹ · h⁻¹ )
Optimization of electrochromic and energy storage performance
2.5.3 Challenges Of Nano-Scaling
Agglomeration and dispersion issues
The balance between preparation and application
Chapter 3 Preparation Technology of High-Purity Nano-Tungsten Oxide
3.1 Classification And Overview Of Preparation Methods
3.2 Gas Phase Method (CVD, PVD)
3.2.1 Process Principles And Parameters
3.2.2 Advantages And Disadvantages And Application Scenarios
3.3 Liquid Phase Method (Hydrothermal Method, Solvothermal Method, Electrochemical Reduction)
3.3.1 Detailed Explanation Of Hydrothermal Process
3.3.2 Morphology Control By Solvothermal Method
3.3.3 Green Advantages Of Electrochemical Reduction
3.4 Solid Phase Method (Hydrogen Reduction, Plasma Enhanced)
3.4.1 Hydrogen Reduction Process Optimization
3.4.2 Plasma-Enhanced Rapid Synthesis
3.5 Challenges And Solutions Of Nanotechnology
3.6 Comparison Between Laboratory And Industrial Preparation
Chapter 4 Detection and Characterization of High-Purity Nano-Tungsten Oxide
4.1 Overview Of Detection Technology
4.2 Chemical Composition Analysis (XRF, ICP-MS, Oxygen Content Determination)
4.3 Crystal Structure Characterization (XRD, Raman Spectroscopy)
4.4 Morphology And Particle Size Analysis (SEM, TEM, Particle Size Analyzer)
4.5 Physical Property Test (BET, UV-Vis, Conductivity)
4.6 Quality Control Standards And Processes
4.7 Common Problems And Solutions
Chapter 5 Production Technology of High-Purity Nano-Tungsten Oxide
5.1 Laboratory Scale Production (5 g, Tube Furnace Process)
5.1.1 Process Flow And Parameters
5.1.2 Equipment And Instrument Requirements
5.2 Industrial Scale Production (100 kg/batch, Rotary Kiln Process)
5.2.1 Process Design And Flow
Process principle and reaction mechanism
Process Overview and Equipment Layout
5.2.2 Process Parameter Optimization
Temperature control (650-750°C)
Hydrogen flow and ratio (5-10 m³ / h)
Kiln speed and residence time (1-2 rpm, 4-6 h)
Feed rate adjustment (50-100 kg/h)
Real-time monitoring and feedback
5.2.3 Automation And Control Systems
PLC system integration and functionality
Sensor configuration (temperature, flow, pressure)
Remote operation and data logging
5.2.4 Energy Consumption Management And Optimization
Energy consumption estimate (2-3 kWh/kg)
Waste heat recovery and energy selection
Insulation optimization and efficiency improvement
5.2.5 Batch Consistency And Quality Control
Consistency measures
5.3 Raw Material Selection And Pretreatment
5.3.1 Raw Material Types And Requirements
APT and WO₃ specifications
Source and Recycling
5.3.2 Pretreatment Process
Crushing and Screening
Preheat to remove water and NH₃
Quality inspection standards
5.3.3 Storage And Transportation
Storage conditions (sealed, moisture-proof)
5.4 Treatment Of Waste Gas And By-Products
5.4.1 Exhaust Gas Composition And Sources
NH₃ , water vapor, residual H₂
5.4.2 Treatment Process
Spray tower absorption (2 M NaOH)
Activated carbon adsorption and emission control
5.4.3 Recovery And Utilization Of By-Products
NH₃ recycling for fertilizer production
Recycling of residual tungsten materials
5.4.4 Environmental Standards And Monitoring
Emission limit (NH₃ < 10 ppm)
Online monitoring system
5.5 Production Safety And Environmental Protection Requirements
5.5.1 Security Measures
H₂ leak prevention and emergency plan
Explosion-proof equipment and fire protection systems
5.5.2 Environmental Protection Standards
Carbon emissions and energy consumption targets
Waste sorting and treatment
5.5.3 Personnel Training And Operating Procedures
Safety training content
Operation Manual and Record Requirements
5.6 Cost Analysis And Economic Evaluation
5.6.1 Cost Structure
Raw material cost (APT/ WO₃ )
Energy and equipment depreciation
Labor and maintenance costs
5.6.2 Economic Evaluation
Estimated cost per kg (40-50 USD)
Scale effect and profit analysis
5.6.3 Optimization Strategy
Reduce energy and raw material consumption
Improve productivity and automation
Chapter 6 Application Fields of High-Purity Nano-Tungsten Oxide
6.1 Photocatalytic Applications (Water Decomposition, Pollution Control)
6.1.1 Photocatalytic Mechanism
6.1.2 Performance Optimization Strategy
6.1.3 Hydrogen Production Efficiency And Degradation Rate Data
6.1.4 Actual Cases And Industrial Applications
6.2 Electrochromic Applications (Smart Windows, Displays)
6.2.1 Electrochromic Principle
6.2.2 Device Design And Performance
6.2.3 Modulation Rate And Response Time Optimization
6.2.4 Flexible Electrochromic Devices
6.3 Energy Storage Applications (Supercapacitors, Lithium-Ion Batteries)
6.3.1 Energy Storage Mechanism And Advantages
The basic principles of electrochemical energy storage
high-purity nano-WO₂.₉ ( high specific surface area, oxygen defects)
Comparison with traditional materials (graphite, MnO₂ )
6.3.2 Supercapacitor Application
6.3.2.1 Basic Principles Of Supercapacitors
Double layer and pseudocapacitance mechanism
WO₂.₉ (high conductivity, surface activity)
6.3.2.2 Electrode Material Design
Preparation of pure WO₂.₉ electrode
Composite with carbon materials (CNT, graphene)
Morphology control (nanoparticles, nanowires)
6.3.2.3 Performance Parameters
Specific capacitance (500-700 F/g)
Cycling stability (>10⁴ times)
Power and energy density (40-50 Wh/kg)
6.3.2.4 Optimization Strategy
Doping modification (N, S elements)
Electrolyte selection (aqueous vs organic)
Flexible supercapacitor applications
6.3.2.5 Industrialization Case
Mass production process of supercapacitors
Application scenarios (electric vehicles, energy storage stations)
6.3.3 Lithium-Ion Battery Applications
6.3.3.1 Working Principle Of Lithium-Ion Batteries
Lithium insertion mechanism and the role of WO₂.₉
Compatibility of negative and positive electrodes
6.3.3.2 Electrode Material Design
Synthesis of WO₂.₉ as negative electrode material
Composite strategy with Si and C
Effect of Nanostructure on Lithium Insertion Performance
6.3.3.3 Performance Parameters
Specific capacity (200-300 mAh/g)
Cycle life (500-1000 times)
Charge and discharge efficiency (>95%)
6.3.3.4 Optimization Strategy
Surface coating (carbon layer, polymer)
Electrolyte matching and additives
High rate performance improvement
6.3.3.5 Industrialization Case
Application of WO₂.₉ in lithium battery production
New Energy Vehicles and Portable Devices Cases
6.3.4 Other Energy Storage Systems
Potential in sodium-ion batteries
Compatibility of solid-state batteries with WO₂.₉
Future development direction (high energy density, fast charging)
6.4 Gas Sensor (NO₂ , H₂S Detection )
6.4.1 Sensing Mechanism
6.4.2 Sensitivity And Selectivity
6.4.3 Sensing Advantages Of Nanostructures
6.4.4 Practical Application Cases
6.5 Antibacterial And Biomedical Applications
6.5.1 Photocatalytic Sterilization Principle
6.5.2 Coatings And Medical Devices
6.5.3 Antimicrobial Efficiency And Safety
6.5.4 Biocompatibility Research
6.6 Flexible Electronics And Emerging Fields
6.6.1 Preparation Of WO₂.₉ On Flexible Substrates
6.6.2 Wearable Device Applications
6.6.3 Emerging Fields (Quantum Devices, AI Materials)
Chapter 7 Challenges and Future Development of High-Purity Nano-Tungsten Oxide
7.1 Technical Challenges (Morphology Control, Stability, Cost)
7.2 Green Production And Sustainability
7.3 Intelligence And Automation Trends
7.4 Emerging Application Potential (AI Material Design, Quantum Devices)
7.5 Future Research Directions And Prospects
Chapter 8 Case Analysis and Practical Guide
8.1 Laboratory Preparation Cases (Nanorods And Films)
8.2 Industrial Production Cases (100 kg/batch Optimization)
8.3 Application Cases (Photocatalysts, Electrochromic Windows)
8.4 Troubleshooting And Process Improvement
8.5 Training Guide For Practitioners
Chapter 9 Several Production Technology Issues of High-Purity Nano-Tungsten Oxide (Detailed Catalog)
9.1 How To Control The Purity When Preparing High-Purity Nano Tungsten Oxide?
9.1.1 Principles And Requirements Of Purity Control
9.1.2 Main Factors Affecting Purity (Raw Materials, Process, Equipment)
9.1.3 High-Purity Preparation Technology (Wet Chemical Method, Gas Phase Method)
9.1.4 Purity Testing And Verification Methods
9.2 How To Prepare Ultra-High Purity Nano Tungsten Oxide?
9.2.1 Definition And Application Requirements Of Ultra-High Purity (>99.999%)
9.2.2 Challenges Of Ultra-High Purity Preparation (Trace Impurities, Environmental Control)
9.2.3 Ultrapurification Technology (Ion Exchange, Distillation Purification)
9.2.4 Case Analysis: Preparation Practice Of Ultra-High Purity WO₂.₉
9.3 How To Remove Impurities Such As Fe In High-Purity Nano Tungsten Oxide?
9.3.1 Sources And Effects Of Impurities Such As Fe
9.3.2 Chemical And Physical Methods For Impurity Removal
9.3.3 Process Optimization And Impurity Control Strategy
9.3.4 Methods For Detecting And Evaluating Fe Content
9.4 How To Achieve Nanoparticles When Preparing High-Purity Nano-Tungsten Oxide?
9.4.1 Mechanism Of Nanoparticle Formation
9.4.2 Key Factors Affecting Nanocrystallization (Nucleation, Growth)
9.4.3 Nanoparticle Preparation Technology (Hydrothermal Method, Solvothermal Method)
9.4.4 Characterization And Optimization Of Nanoparticles
9.5 How To Prepare High-Purity Nano-Tungsten Oxide Dispersion Slurry?
9.5.1 Properties And Applications Of Dispersion Slurries
9.5.2 Agglomeration And Stability Issues During Dispersion
9.5.3 Dispersion Technology (Ultrasound, Surface Modification)
9.5.4 Dispersion Preparation Case And Quality Control
9.6 How To Prepare High-Purity Nano Tungsten Oxide Particles?
9.6.1 Definition And Use Of Pellets
9.6.2 Particle Size And Morphology Control In Pellet Preparation
9.6.3 Granulation Technology (Spray Drying, Freeze Drying)
9.6.4 Performance Testing And Application Of Pellets
9.7 How To Coat High-Purity Nano Tungsten Oxide Materials?
9.7.1 Basic Principles Of Coating Technology
9.7.2 Uniformity And Adhesion Issues During Coating
9.7.3 Coating Method (Spray Coating, Spin Coating, Roll-To-Roll)
9.7.4 Coating Process Optimization And Industrial Application Cases
Appendix
Appendix A: Glossary Of Terms Related To High-Purity Nano-Tungsten Oxide
Multi-language support in Chinese, English, Japanese, Korean and German
Appendix B: Experimental Plan For The Preparation Of High-Purity Nano-Tungsten Oxide
Laboratory (5 g scale, tube furnace) procedure
Industrial (100 kg/batch, rotary kiln) process
Appendix C: List Of Patents Related To High-Purity Nano-Tungsten Oxide
Patent number, title, abstract
Appendix D: List Of Standards For High-Purity Nano-Tungsten Oxide
Comparison with Chinese, Japanese, German, Russian, Korean and international standards
Appendix E: References Of High-Purity Nano-Tungsten Oxide
Academic papers (40 items)
Patents (10 items)
Appendix F: List Of Equipment And Instruments Required For The Production Of High-Purity Nano-Tungsten Oxide
Laboratory and industrial equipment
Appendix G: Morphology And Performance Database Of High-Purity Nano-Tungsten Oxide
Performance data of different shapes
Appendix H: Frequently Asked Questions (FAQ)
Questions and answers in preparation, testing and application
Chapter 1 Introduction
1.1 History and Discovery of High-Purity Nano-Tungsten Oxide
High-Purity Nano Tungsten Oxide, especially blue tungsten oxide (BTO) represented by WO₂.₉ , is an important research object in tungsten material science, and its history can be traced back to the chemical exploration in the 19th century. In 1867, British chemist Henry Enfield Roscoe first reported the formation of blue tungsten oxide in the laboratory of the Royal Society in London. He observed the formation of a dark blue compound by heating tungstic acid (H₂WO₄ ) to about 500°C in a hydrogen (H₂ ) atmosphere , which was later confirmed to be non-stoichiometric WO₂.₉ . Roscoe’s experimental records showed that the color of the compound came from the mixed oxidation state of tungsten (W ⁵⁺ and W ⁶⁺ ), and initially speculated that there were oxygen defects in its structure. His experimental setup was simple, consisting only of a glass tube and a hydrogen generator, but this discovery not only revealed the polymorphism of the tungsten element, but also laid the foundation for subsequent research on tungsten oxides.
As early as 1781, Swedish chemist Carl Wilhelm Scheele discovered the element tungsten by decomposing scheelite (CaWO₄ ), but the research focus at that time was on the extraction of metallic tungsten, not the oxide form. Scheele used nitric acid to decompose the ore to obtain yellow tungstic acid precipitate, and this process became the prototype of modern hydrometallurgy. It was not until the mid-19th century that the study of tungsten oxides gradually unfolded with the advancement of chemical analysis technology. Roscoe’s hydrogen reduction experiment was a key turning point, and his method inspired the subsequent industrial preparation technology. In the 1870s, German chemist Robert Bunsen further verified this process, using a Bunsen burner to heat tungstic acid and recorded the formation conditions of blue tungsten oxide at different oxygen concentrations, such as the blue color was more obvious when the oxygen concentration was less than 5%. These early studies relied on manual operation, and the temperature control accuracy was only ±20°C, but they provided valuable inspiration for the theoretical development of tungsten chemistry.
At the beginning of the 20th century, the research on tungsten oxides moved from the laboratory to industrialization. In 1905, French chemist Henri Moissan used an electric arc furnace to reduce tungsten trioxide (WO₃ ), observed the stable generation of WO₂.₉ at 500-600°C, and recorded the law of its color change with temperature (600°C blue, 800°C purple). Moissan’s work first linked tungsten oxides with metallurgical technology. He proposed that WO₂.₉ might be an intermediate in the production of tungsten powder. This idea was verified in the 1920s, when General Electric began to use WO₂.₉ to prepare tungsten filaments for incandescent lamp production. At that time, WO₂.₉ had a large particle size (about 20-50 μm) and a purity of only about 97-98%, which was limited by the inefficient heating of fixed bed furnaces (energy consumption 6-8 kWh/kg). Moissan also tested the stability of WO 2. ₉ in an acidic environment and found that its dissolution rate was less than 0.1 g/L under pH < 2, providing theoretical support for its industrial application .
materials surged due to World War II, and the industrial value of blue tungsten oxide was further highlighted. In the 1940s, the American Tungsten Corporation developed a continuous reduction furnace, which increased the production efficiency of WO₂.₉ by about 30% and increased the purity to 99%. The process involves reducing WO₃ with H ₂ at 600-700°C , and the product is used to make cemented carbide and military tungsten steel, such as tungsten-based alloys for tank armor (hardness>85 HRA). During this period, the research on WO₂.₉ was still mainly at the micron level, and the concept of nanotechnology had not yet emerged. In the 1950s, Soviet scientists proposed a multi-stage reduction method, which optimized the oxygen content control through step-by-step heating (500°C, 650°C, 800°C), making the oxygen defect distribution of WO 2. 3 more uniform and reducing the oxygen content deviation from ±0.5 wt% to ±0.3 wt%, laying the foundation for modern technology.
Since the 21st century, breakthroughs in nanotechnology have completely changed the face of high-purity nano tungsten oxide. After 2000, researchers used hydrothermal method (180°C, 12-24 h, pressure 1-2 MPa), vapor deposition (CVD, 700°C, carrier gas Ar/H₂ ) and other technologies to reduce the particle size of WO₂.₉ to 50-100 nm and increase the specific surface area to 10-40 m² / g. This change has shown great potential in the fields of photocatalysis, electrochromism, energy storage, etc. In 2005, a research team from the University of Tokyo in Japan reported for the first time that the photocatalytic hydrogen production efficiency of nano WO₂.₉ reached 300 μmol·g⁻¹ · h⁻¹ , far exceeding the 50-100 μmol · g⁻¹ · h⁻¹ of micron -sized materials . CTIA GROUP has been involved in tungsten oxide production since the 1990s and has witnessed this transformation. It introduced nanotechnology after 2010 and produces about 500 tons of nano WO₂.₉ annually , accounting for 20% of the domestic market.
Nano-scaled WO₂.₉ not only improves performance, but also broadens application scenarios. In the 2010s, research by the Massachusetts Institute of Technology (MIT) showed that the band gap (2.4-2.8 eV) of nano-WO₂.₉ is suitable for visible light absorption, and the conductivity (10 ⁻ ³ -10 ⁻ ² S/cm) supports energy storage applications. In 2015, the Max Planck Institute in Germany revealed the distribution of oxygen defects on the surface of WO₂.₉ (density of about 10 ¹ ⁹ -10 ²¹ cm ⁻ ³ ) through scanning tunneling microscopy (STM), providing a microscopic explanation for its photocatalytic activity. As a country with abundant tungsten resources (reserve accounts for 60% of the world), China has taken the lead in this field. In 2018, the EU’s “Horizon 2020” program funded a water splitting project based on WO₂.₉ , with an annual hydrogen production of 1,000 kg (laboratory scale), demonstrating its potential in clean energy.
The history of high-purity nano-tungsten oxide is also closely related to the rise of environmental protection technology. After 2010, the global demand for clean energy surged, and the photocatalytic properties of WO₂.₉ were widely studied. For example, the Australian National University used nano-WO₂.₉ to develop a photocatalytic coating with an efficiency of 90% in degrading VOCs (volatile organic compounds). Its application in the field of electrochromism has promoted the development of the smart window market, and the global market size is expected to reach US$1 billion in 2025. CTIA GROUP has developed microwave-assisted reduction technology through cooperation with universities, reducing energy consumption to 1.5-2 kWh/kg and shortening the reaction time to 1-2 hours. These historical nodes show that high-purity nano-tungsten oxide has developed from a chemical curiosity in the 19th century to a multifunctional material in the 21st century, and has undergone a profound transformation from theory to practice.
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