Preparation Of MOFs/g-C₃N₄ Heterojunction Material And Study On Photoreduction Of Water

In the past few decades,searching for various photocatalysts has become a hot research direction to solve the energy crisis.In order to make full use of high-energy,stable source,non-toxic and harmless sunlight resources,researchers have discovered semiconductor materials with excellent photocatalytic activity.However,most semiconductor materials face problems such as poor visible light absorption and stability,and rapid recombination of photo-generated charges and holes,which limit their development.So far,various methods have been developed to improve the photocatalytic efficiency of the catalyst.Among them,the construction of a heterojunction is considered to be the most direct and effective method.In this paper,metal-organic framework（MOFs）materials are used as the main research object.Aiming at the shortcomings of low quantum efficiency and easy recombination of photo-generated carriers,g-C₃N₄ materials are used to construct highly efficient and stable MOFs/g-C₃N₄ heterostructures.Taking advantage of the adjustable structure of MOFs,starting from both the heterojunction structure and the properties of the heterojunction interface,a new type of 2D-2D heterojunction and bonded heterojunction photocatalyst are constructed to realize the efficient transfer and separation of photo-generated charges and improve Photocatalytic performance of composite materials.The main research contents are as follows:（1）Through the in-situ growth method,the carboxyl modified g-C₃N₄-COOH and the ligand terephthalic acid are used to complete the epitaxial growth of Co MOF,thereby successfully constructing chemical bonds at the heterojunction interface and preparing the bonded heterogeneity Co MOF-g-C₃N₄-COOH was used as the junction material,and a systematic study was carried out on the influence of chemical bond construction on the catalytic performance.The results show that:Co MOF is grown interlaced between g-C₃N₄-COOH layers to construct a tighter heterojunction interface,which solves the low photogenerated carrier migration rate caused by electron transport barriers in traditional van der Waals heterogeneous materials.Compound fast and other issues.Co MOF-g-C₃N₄-COOH has good performance of photodegradation of water under visible light to produce hydrogen,with a hydrogen production rate of 233μmol·g^-1·h^-1,and shows good stability.（2）A new type of CoZr-AUBM4 nanosheet metal organic framework material with excellent visible light absorption performance was synthesized and prepared,and a heterostructure photocatalyst CZAG-0.1 was constructed by electrostatic self-assembly method together with g-C₃N₄ nanosheets.The results show that the electron transfer rate of the double-nanosheet heterojunction is higher,which effectively promotes the migration and separation of photogenerated carriers.It is worth noting that,compared to Ni Zr-AUBM4 and g-C₃N₄,and 2D-3D structure heterojunction materials,CZAG-0.1 shows good catalytic activity in the visible light catalyzed water splitting hydrogen production reaction,and the rate of hydrogen production up to 387μmol·g^-1·h^-1.