Carbon,Nitrogen Co-modified Niobium Oxide: Synthesis,Characterization And Its Catalytic Activity For RhB Degradation Under Visible Light

The heterogeneous photocatalysis and semiconductor-based photocatalytic processes have concerned global heed in latest years for prospective applications,including solar hydrogen production by photocatalytic water splitting and the treatment of gas effluents and wastewater through the photodegradation of contaminants.In the course of recent years,a large assortment of semiconductor-based materials has been explored,of which titania is proved to be one of the best candidates as of its chemical stability,low cost,and nontoxicity.However,the major limitations for its wide practical application are low conversion efficiencies and poor reliability,etc.Moreover,the significant issues of the specialist arrangement of viable electron-hole recombination focuses have likewise stayed unsolved yet.Therefore,this work concentrated on searching for efficient semiconductor materials as possible substitutes of TiO₂.The main aim of the work introduced in this thesis was to design and manufacture well-characterized material that would exploit visible light to support photocatalysis,including the degradation of organic compounds in water.In doing so,ecological concerns are,for example,the taking away of contaminations in wastewater.The approach used was to utilize accessible methods to produce elevated surface area material that is active in UV light for photocatalysis,and then design and use post-synthetic modification to support the material for visible light photocatalysis.Carbon,nitrogen co-modified Nb₂O₅ nanowires have been successfully synthesized via a hydrothermal-calcination process with niobium oxalate as a precursor and 2-methylimidazole?Hmim?as not only a structure-directing agent but also a source of nitrogen and carbon.The synthesized C,N co-modified Nb₂O₅nanowires were characterized by scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?,Fourier transform infrared spectroscopy?FT-IR?,high resolution transmission electron microscopy?HRTEM?,and Brunauere-Emmette-Teller?BET?analysis.The formation process of Nb₂O₅ nanowires has been presented in detail by investigating the effects of the Hmim concentration,reaction temperature,co-solvent and calcination temperature.The results showed the optimal synthetic conditions:Hmim concentration,33.33 mmol/L;reaction temperature,180 ⁰C;ethanol?co-solvent?:water,1:2?volumetric ratio?;calcination temperature,350⁰C.The as-prepared Nb₂O₅ nanowires not only exhibited more efficient photocatalytic activity than commercial Degussa P25,N-TiO₂,and Nb₂O₅-CS towards photocatalytic degradation of 10 mg L^-1Rhodamine B?RhB?under visible light but also showed good stability after five cycles.