Study On The Preparation And Photocatalytic Performance Of 3D Semiconductor-type BCN Materials

The rapidly developing nanomaterials have brought 3D nanomaterials into people’s view,and materials such as 3D metals,3D ceramics and 3D aerogels have been widely reported.Boron Carbon Nitride（BCN）is a new ternary-like graphene semiconductor material with adjustable band gap between graphene（zero band gap）and hexagonal boron nitride（band gap=5.6 e V）with high temperature oxidation resistance and thermal stability.Different materials can be prepared by changing the composition and arrangement of B,C and N elements,which are widely used in photocatalysis,electrocatalysis,energy storage and superhard materials.Currently,zero-dimensional,one-dimensional,two-dimensional and aerogel forms of BCN materials have been widely reported,but few three-dimensional BCN materials have been reported.Metal-Organic Frameworks（MOFs）materials can retain their own morphology as self-sacrificing templates,and therefore,studies on the preparation of MOFs-derived materials using MOFs materials as precursors have been widely reported in recent years.In this paper,a novel B-containing three-dimensional MOF precursor was prepared by heating metal salts and boron-containing ligands under the condition of microwave radiation,and its derivative applications were carefully investigated.The details of the study are as follows.（1）Boric acid was used as a bridging ligand to investigate the growth mechanism of mw-MBON-1 materials,and the effects of reaction time,temperature and reactant ratios on their nuclei growth were analyzed using XRD,SEM and other testing methods.Different from the preparation mechanism of the solvent heat method,the microwave radiation method enables the direct reaction of three reagents to prepare MBON-1,which not only shortens the preparation time,but also simplifies the preparation process.Finally,a three-dimensional flower cluster-like MOFs material formed by the assembly of two-dimensional nanosheets was successfully prepared,which laid the foundation for exploring the application of its derivative materials.（2）The BCN materials were successfully prepared by ammoxidation of mw-MBON-1 at900°C.The derived materials perfectly inherited the three-dimensional structure of the precursors.The 3D-BCN material was used as a catalyst to activate PMS for organic degradation,and demonstrated excellent catalytic degradation performance with the assistance of visible light,which could effectively remove the organic pollutants containing benzene ring and other organic dyes at 180 min.The catalyst showed excellent industrialization prospects for water treatment.（3）Three different pyrolysis temperatures of 800℃,900℃and 1000℃were selected to prepare three different derivative materials.The three catalysts were characterized by XRD,SEM,TEM,XPS and FT-IR tests.In this paper,the photocatalytic reduction of O₂ to prepare H₂O₂ was selected to evaluate the catalytic performance of the three different catalysts.Under300 W Xe lamp irradiation conditions,the H₂O₂ productivity within 180 min for two catalysts,3D-BCN-900 and 3D-BCN-1000,was higher than that of g-C₃N₄ and some of its polymers,showing excellent photocatalytic performance.And the reasons for the difference in performance of the three BCN materials were analyzed by the difference in electronic structure for the photocatalytic preparation of H₂O₂ as a novel nonmetallic catalyst.