Design,Synthesis And Application Of Copper Oxide Heterojunction Photocatalyst

Photocatalysis is a widely used technology that has been studied in recentyears and is favored by people.This technology has the advantages of low cost,non-toxicity,economy,environmental protection and high efficiency.Photocatalytic technology can be used to break down water to produce hydrogen,reduce carbon dioxide and degrade organic pollutants.The photocatalytic technology is mainly that the catalyst is exposed to light,and electrons are transitioned to generate electron-hole pairs,thereby degrading organic pollutants.However,in traditional photocatalysts,due to the large band gap,the energy required for electronic transition is large;most of the catalysts are powders,which are difficult to recycle and reuse,which makes it difficult to meet the needs of people in real life.Therefore,researchers are looking for new and efficient photocatalysts that are easy to recycle.Transition Metal oxide semiconductors are widely studied photocatalysts inrecent years.Among them,copper oxide?Cu O?has attracted people's attention because of its 1.2 e V band-type semiconductor.It is widely used in lithium ion batteries,gas sensors,electrochemical sensors,photothermal,photosensitive devices,cathode materials and photocatalysis.In the past ten years,researchers have prepared Cu O with different dimensions in 0 D,1 D,2 D and 3 D,and have achieved satisfactory results in various application fields.Cu O can not only be used as a photocatalytic material,but also can be doped with other metals or form a heterojunction complex with other semiconductors to improve photocatalytic performance.In this paper,different Cu O heterojunction composites were prepared by using copper mesh as the substrate and synthesized Cu?OH?₂ in solution of NaOH and?NH₄?₂S₂O₈ as precursor.The photocatalytic properties of the composites were studied.The main research results are as follows:?1?Based on the copper mesh,the copper mesh was immersed in a mixedsolution of NaOH and?NH₄?₂S₂O₈ to form Cu?OH?₂ nanowires on the surface of the copper mesh,and then vulcanized to form Cu S on the surface of Cu?OH?₂.The vulcanization time was 1 minute,10 minutes,1 hour and 4 hours.Next,in the tube furnace,the Cu S/Cu O/Cu composites with different morphologies were synthesized by calcination at 150?for 1 h in N₂ atmosphere and calcination at 200?for 2 h.Studies have shown that the curing time is the amount of Cu?OH?₂ converted into Cu S and the main factor controlling the morphology.With the aid of hydrogen peroxide?H₂O₂?,through the photocatalytic degradation of methylene blue?MB?,it was found that the catalyst with vulcanization for 10 minutes is relatively better than the photocatalytic performance of other samples.This is because Cu O and Cu S combine to form a heterostructure,broaden the light absorption range and suppress the recombination of electron-hole pairs.?2?Based on the copper mesh,the copper mesh was immersed in a mixedsolution of NaOH and?NH₄?₂S₂O₈ to form Cu?OH?₂ nanowires on the surface of the copper mesh,and then Cu?OH?₂/Cu was immersed in the mixture solution of zinc acetate dihydrate?Zn?CH₃COO?₂·2H₂O?and sodium hydroxide?NaOH?for 10minutes,and calcined at 150?for 10 minutes in a tube furnace,The process was repeated 3 times.Then,Cu?OH?₂/Cu was immersed in a mixed solution containing 20mmol of zinc nitrate hexahydrate?Zn?NO₃?₂·6H₂O?and 20 mmol of hexamethylenetetramine?HMTA?,and hydrothermal reaction at 90?for 10 minutes,20 minutes,30 minutes,40 minutes,1 hour and 2 hours.Zn O with different morphologies were prepared.Finally,Zn O/Cu O/Cu heterostructures composites with different morphologies were obtained by calcination at 150?for 1 h in tube furnace and 2 hours at 200?.The prepared material was used as a catalyst and was used to reduce Cr⁶⁺under the irradiation of xenon lamp.The effect of reducing Cr⁶⁺by different catalysts was compared,It was found that the sample reacted at 90?for 30minutes had the best effect in reducing potassium dichromate.