Controllable Preparation Of Perovskite-type Potassium Niobate Nanomaterials And Propertites Research

KNbO₃ is one of the most important perovskite nanomaterials,with excellent nonlinear,photocatalysis and electrocatalytic properties.At the same time,perovskite-type KNbO₃ NMs have the characteristics of easy preparation,low toxicity,large specific surface area,large second-order nonlinear optical coefficient and high stability under light irradiation.It has been applied to the waveguide,multiplier,holographic storage and other fields.Therefore,the application of KNbO₃ nonlinear optical properties and photocatalysts has been extensively studied.Since the KNbO₃ have an empty d orbital in the conduction band,they have rich crystalline structure.Different structures of KNbO₃ NMs are expected to have different physicochemical properties.For instance,most previous studies about the properties of potassium niobate nanomaterials are limited to the study of single crystal form.Only a thorough understanding of structure-function relationships in well-defined model catalysts can add new dimensions to design catalysts at an atomiclevel.In this paper,perovskite-type potassium niobate nanomaterials with monoclinic phase,orthorhombic crystal phase and cubic phase were prepared by hydrothermal method by selecting appropriate niobium source and addition of potassium salt.The structure and morphology of the prepared materials were analyzed by XRD and SEM.The nonlinear optical properties,photocatalytic properties and electrocatalytic properties of monoclinic,orthorhombic and cubic perovskite-type KNbO₃ NMs were studied.At the same time,the relationship between structure and function was discussed.It was found that the perovskite-type potassium niobate nanomaterials produced an adjustable second harmonic emission in the wide fundamental frequency spectrum?800-1050 nm?.And the second harmonic intensity is dependent on the crystal phase.The monoclinic KNb O₃ exhibits the best nonlinear optical properties,while the cubic KNbO₃ has the worst nonlinear optical properties,but the cubic KNbO₃ shows the best photocatalytic performance and electrocatalytic performance,the properties dependent on the structure heavily.