Application And Research Of Tungsten Oxide-based Composite Materials In Photoelectric Catalysis And Supercapacitors

Tungsten oxide based electrodes have a lot of unique character such as high theoretical specific capacitance,can proceed reversible redox reactions,low cost,and environmentally friendly.These character can make tungsten oxide based electrodes a promising candidate for supercapacitor electrode.Besides,the reversible redox reaction between the electrode and electrolyte could produce the pseudocapcaitance which higher than the double layer capacitance.However,the electrical conductivity of tungsten oxide based electrodes are always poor and will decrease the transmission efficiency.These disadvantages are harmful to improve the supercapacitance.Tungsten trioxide is also a promising candidate for photoelectrochemistry?PEC?due to the appropriate band gap?2.6–2.8 eV?,excellent charge transfer and diffuse ability.Remarkably,the theoretical photocurrent density could reach to 4 mA cm-2 at the illuminate of AM 1.5 G photosource.However,nanocrystalline WO₃ always exhibits great recombination of photogenerated electron-hole pairs,which significantly reduct the photocatalytic activity.Besides,during water splitting,WO₃ endures photocorrosion owing to the construction of peroxo-species,which reduced the stability of photocatalytic system.Herein,we have made some effective modifications to tungsten-oxide-based materials and combined them with other suitable materials to form composites to improve their super-electrical and photoelectrocatalytic properties.The tungsten trioxide nanosheet and the activated carbon cloth were composited to obtain a composite of the mesoporous tungsten trioxide nanosheet and the activated carbon cloth.Due to the excellent electrical conductivity of carbon cloth,the supercapacitor properties of the composite system are greatly improved,and the DFT calculations demonstrate that compared to?002?and the?020?facets,the?200?facet of the tungsten trioxide nanosheet has the strongest sodium ion adsorption capacity,and therefore has the strongest redox ability,which can greatly improve the supercapacitor performance.We have prepared aerogels of tungsten dioxide particles and chitosan carbon composites for supercapacitor.Tungsten dioxide has many oxygen vacancies so that its electron transport efficiency can be increased.And carbonization of chitosan can give porous carbon,which is a carbon material with a large specific surface area.The increase in specific surface area and electrical conductivity can effectively improve the performance of the supercapacitor.We have prepared tungsten trioxide nanosheets and hollow titanium dioxide quantum dots composite,and this composite can effectively solve the problem of easily recombination of tungsten trioxide photocarriers.And hollow titanium dioxide quantum dots have a high specific surface area which can increase the absorption of light and contact with the electrolyte,thereby greatly enhancing the photoelectrocatalytic performance.