Study On The Site Control And Photocatalytic Performance Based On Single Tungsten Atom Oxide

Focusing on the problems of energy shortage and environmental pollution,the development of environmental remediation technology and new alternative clean energy has become a fundamental and urgent scientific research task worldwide.Owing to photocatalysis can use natural solar energy without additional energy consumption,it has become one of the most promising technologies.Moreover,photogenerated carrier’s energy is beneficial to overcome energy barrier that is difficult to occur in general conditions.The photocatalytic materials include:oxides,carbon-based compounds,etc.Among them,transition metal oxides have received extensive attention due to their low-cost,non-toxicity,and adjustable energy band structure.However,most photocatalytic mateirals have not been widely used.It remains the bottlenecks of their efficiency,selectivity and lifetime.In recent years,with the vigorous development of single-atom catalysts（SAC）,it is a new strategy to design and discuss the performance of catalysts at the atomic-scale site.The construction of single site can pontentially improve the activity（efficiency）and selectivity,and combining the advantages of homogeneous catalyst and heterogeneous catalyst.Recently,our research group has proposed single metal atom oxide（SMAO）site system,i.e.the single metal atom coordinated with the surrounding oxygen atoms.In this thesis,the research based on single tungsten atom oxide（STAO）were carried out.The main research work includes the following three aspects:（1）Preparation of single tungsten atom oxide（STAO）,its microstructure and photocatalytic degradation of methyl orange were explored and characterized.The photocatalytic degradation rate of STAO reaches 0.24 s^-1.（2）Based on STAO,a heterogeneous catalyst with Bi₂WO₆/Bi OCl heterojunction was designed and synthesized.The catalyst has high activity and high selectivity for the photocatalytic reduction of CO₂ to CO.The photoreduction effieincy is about 5 times and 4.2 times higher than that of Bi₂WO₆ and Bi OCl,resepcitvley.（3）Based on the design and synthesis ideas of STAO,it is extended to other metal oxides,and designed ultra-small sub-nanometer TiO_x clusters（containing single atom and small nano clusters）were anchored on the surface of plasma Ag/Ag Cl as excellent catalysts.Under simulated sunlight,the photodegradation activity of TiO_x@Ag/Ag Cl for tetracycline（TC）is extremely high,about 21.7 times higher than that of Ag/Ag Cl.