Construction Of Sub-stoichiometric Tungsten Oxide Substrate And Amorphous Structure And Their Application

As an n-type semiconductor material,tungsten oxide has attracted the attention and research of many scientists due to its adjustable composition,variable structure,wide source,and excellent performance.WO₃ can effectively adjust its electronic structure through its structural changes and the formation of sub-stoichiometry,so that it has excellent performance in various applications,such as photo/electrocatalysis,gas sensing and photothermal conversion,which is widely used.Among them,the introduction of oxygen defects and amorphous conversion make the sub-stoichiometric WO_3-x have special properties.The introduction of defects makes it an effective metal-loaded substrate.In addition,for sub-stoichiometric WO_3-x with unique atomic structure,the amorphization study is carried out by simple method to make it stronger light absorption capacity in the visible and near-infrared region.Therefore,in this paper,the defect state WO_3-x is constructed through defects to enable it to have a strong interaction with the precious metal Au,and then Au/WO_3-x nanocomposites are prepared in a simple and effective manner.The structure of WO_2.72 undergoes amorphization and its properties are explored.The main research contents are as follows:?1?Study on the preparation of nanocomposites:in-situ growth of Au nanoparticles on defective WO_3-xWO_3-x with oxygen defects were first prepared by a simple chemical reduction method.The introduction of oxygen defects endows WO_3-x with weak reducing power.By directly mixing defective WO_3-xand oxidizing Au³⁺,Au³⁺is reduced to Au⁰,and the Au nanoparticles obtained by the reduction are directly grown on defective WO_3-x.This method to prepare metal/semiconductor nanocomposite avoids the effect of adding reducing agents and stabilizers on the materials.The synthesis method is simple,novel and unique,and provides better research foundation for the synthesis of precious metal/semiconductor nanocomposites.?2?Study on electrocatalytic nitrogen reduction reaction?NRR?performance of Au/WO_3-xnanocomposites and exploration of nitrogen reduction mechanismAu/WO_3-x nanocomposite was used as a catalyst for electrocatalytic nitrogen reduction.The test results showed that the rate of ammonia synthesis up to 23.15?g·h^-1·mg^-1,and the Faraday efficiency reached 14.72%,which shows excellent catalytic performance.Based on experimental results and theoretical calculations,we further explore and explain the mechanism of electrocatalytic nitrogen reduction.?3?Supercritical CO₂-assisted amorphization of WO_2.72 and its high-efficiency of photothermal conversionWith the assistant of supercritical CO₂,the crystalline phase of WO_2.72 was transformed into amorphous WO_2.72,and amorphous WO_2.72 shows strong light absorption in the visible and near infrared light regions.Compared with other methods for preparing amorphous materials,this method is novel,unique,and simple.Its photothermal conversion efficiency reached 52.5%,which shows excellent photothermal conversion performance.This study provides a good idea for the preparation of amorphous materials and the development of photothermal reagents.