Nano tungsten trioxide (WO?) exhibits significant advantages in multiple fields due to its unique nanoscale effects and structural properties. Below are its main characteristics and applications.
I. Structural Characteristics
High Specific Surface Area: Nano-scale WO? has a larger specific surface area, significantly increasing the number of surface active sites and enhancing its ability to interact with other substances such as gases, liquids, or light.
Controllable Morphology: Through synthetic methods (such as hydrothermal synthesis and vapor deposition), different morphologies such as nanoparticles, nanowires, nanosheets, and porous structures can be prepared to meet various application needs.
Quantum Size Effect: The nanoscale size leads to changes in the electronic structure, affecting physical properties such as light absorption and conductivity. For example, the band gap can be adjusted to optimize the light response range.
Stable Crystal Structure: Nano tungsten trioxide possesses high crystallinity and well-organized nanostructure, enabling it to maintain good stability under extreme conditions such as high temperature and high pressure.
II. Chemical Properties
Solubility: Nano tungsten trioxide is insoluble in water but soluble in hot alkaline solutions. It is slightly soluble in hydrofluoric acid but insoluble in dilute acids.
Redox Property: Nano tungsten trioxide can participate in redox reactions. For instance, at high temperatures, it can be reduced to metallic tungsten or tungsten oxides of lower valence states. Simultaneously, it can also act as an oxidant in certain chemical reactions.
Chemical Stability: Nano tungsten trioxide is relatively stable at room temperature but may decompose or react with other substances under certain conditions (such as high temperature, strong acids, or strong bases).
III. Optical and Electrical Properties
Broad Spectrum Absorption: It can absorb ultraviolet to near-infrared light, enabling photochromism, suitable for photothermal conversion and broad-spectrum photoelectric devices.
Photosensitivity: Under illumination, it may undergo photochemical reactions, making it potentially valuable in areas such as photocatalysis (photolysis of water to produce hydrogen) and optical storage.
High Carrier Mobility: The nanostructure reduces grain boundary defects, improving electron transport efficiency and enhancing photoelectric conversion performance.
Electrocatalytic Activity: It is active in oxygen evolution reactions (OER) and carbon dioxide reduction (CO?RR), suitable for clean energy conversion.
Electrochromic Effect: It undergoes reversible color changes under an applied voltage, finding applications in smart windows and energy-efficient displays.
Gas Sensitivity: It is sensitive to gases such as NOx, NH?, and H?S, commonly used in high-sensitivity gas sensors with fast response times and good selectivity.
Ion Insertion/Extraction Capability: As an electrode material for lithium-ion or sodium-ion batteries, the nanostructure shortens ion diffusion paths, enhancing charging and discharging efficiency.
IV. Application Fields
Environmental Treatment: Photocatalytic degradation of pollutants, air purification, and wastewater purification.
Energy Storage and Conversion: Lithium/sodium-ion batteries, supercapacitors, solar cells, and fuel cell catalysts.
Smart Devices: Electrochromic smart windows and low-power displays.
Biomedicine: Photothermal treatment of tumors (excited by near-infrared light) and antibacterial materials.
Safety Monitoring: Industrial exhaust gas detection and flammable/explosive gas sensors.
Fire-resistant Materials: Fire-resistant, refractory, and thermal shock-resistant materials.
