Fabrication Of Flexible Zirconia Nanofibrous Membranes Loaded With Ag₂O-TiO₂ For Photocatalysis

In recent years,the problem of environmental pollution is becoming increasingly serious.At present,there are many ways to treat the environmental pollution,such as physical sedimentation,chemical oxidation,microbe treatment method and so on.But these methods have many shortcomings,for instance,incomplete degradation,high cost,complex,etc.As a new type of environment-friendly technology,photocatalysis technique have attracted more and more attention due to it possessing non-toxic,low cost,good biocompatibility.However,the photocatalytic materials are dominant in the form of particles,which limits the practical application to some extent because of small surface area,low activity,and secondary pollution.So,in order to improve the photocatalytic performance,the particles were usually loaded to the metal net,non-woven fabrics or honeycomb ceramics by the spraying technique.But what`s unfortunate is that these methods also have some weaknesses,such as easy to fall off and non-uniform distribution.In view of these problems,some effort has been devoted to fabricating inorganic nanofibers by electrospinning due to their high chemical and thermal stability,high activity in recent years.But the brittleness of current inorganic membranes significantly limits their practical applications.Therefore,it is the key point to prepare the flexible inorganic nanofibrous membranes with high photocatalytic activity and stable mechanical properties.In this experiment,the flexible ZrO₂ nanofibrous membranes load with TiO₂ nanoparticles?YSZ-TiO₂?were firstly prepared by electrospinning method.Then,the Ag₂ O was uniformly coated on the surface of nanofibers by precipitation process.P-n nanoheterojunction was constructed between Ag₂ O coating and TiO₂ nanoparticles,which will reduce the recombination rate of photoelectrons and holes.Finally,the flexible ZrO₂ nanofibrous membranes loaded with high active Ag₂O-TiO₂?AZT?were obtained via a combination of electrospinning technique and precipitation process.In order to study the effect of particle concentration on the morphology and flexibility of the YSZ-TiO₂ nanofibrous membranes.Different concentration of TiO₂ NPs?1wt%,5wt% and 10wt%?were added to the precursor solution.The results showed that YSZ-TiO₂ nanofibrous membranes with the optimum TiO₂ NPs concentration of 5wt% exhibit excellent flexibility and the nanoparticles dispersion was uniformity.Moreover,the specific surface area of YSZ-TiO₂ nanofibrous membranes increased with increasing of the concentration of TiO₂ NPs,however,flexible of membranes decreased.When the concentration of the particle reached 10wt%,a large number of particles aggregated on the surface of nanofibers and nanofibrous membranes became brittle.Therefore,the YSZ-TiO₂?5wt%?nanofibrous membranes were selected as the composite semiconductor substrate.Then,study the effect of different amounts of AgNO₃ on the morphology and photocatalytic activity through the precipitation method.Different concentration of AgNO₃?0.02wt%,0.06wt% and 0.10wt%?were selected.The results showed that the photocatalytic activity of the AZT membranes increased with the increase of AgNO₃ contents,reaching a maximum value at 0.06wt%,and then no change with the increase of the concentration.Therefore,when the concentration of TiO₂ NPs and AgNO₃ is 5wt% and 0.06wt%,respectively,the AZT nanofibrous membranes showed robust flexibility and excellent photocatalytic activity.The UV photocatalytic performance of the flexible AZT nanofibrous membranes with a band gap energy of2.89 e V and good reversibility of 5 cycles,was superior to the commercial catalyst P25 for photocatalytic degradation of methylene blue?fast degradation within 35 min?.In summary,a novel flexible p-n nanoheterojunction photocatalyst with YSZ nanofibrous membranes as backbone to support the TiO₂ NPs and Ag₂ O nanocrystals has been prepared by electrospinning technique and precipitation process.Considering the simplicity of the fabrication process and the extraordinary photocatalytic activity,the as-prepared AZT provide not only a promising method for the degradation of dye pollutants,but also provides a new perspective for the study of photocatalytic membranes.