Ag₃PO₄-based Composite Materials For Photocatalytic Water Splitting: Design, Synthesis And Properties

In recent years,the situation about energy shortage and environmental pollution is quite serious,and also a major challenge facing mankind.How to effectively solve these two problems has become the focus of the whole society,but also the current scientific research areas needed to solve about the key issues.Solar energy is a clean,sustainable utilization and non-pollution energy.Some semiconductor materials with certain band location can effectively utilize solar photocatalytic decomposition of water to produce hydrogen and oxygen,that converts light energy to chemical energy.So based on semiconductor materials of solar photocatalytic technology is considered to be the most effective way to solve the environment pollution and energy shortage.Design and synthesis of new and efficient composite materials used in solar photocatalytic decomposition of water research has become the current research hot and difficult problems.In this paper,the composite materials with fixed composition and microstructure were prepared by the effective synthesis of semiconductor materials（such as C₃N₄,MoS₂）and silver phosphate semiconductor materials and applied to solar photocatalytic decomposition of water:（1）Combination the methods of precursor copolymerization modification,high temperature sintering,electrostatic driving self-assembly and reaction in-situ sufficiently.And electrostatic adsorption of positively charged silver ions on modified g-C₃N₄ material of non-metallic elements.Implementation on controllable preparation of modified g-C₃N₄/Ag3PO4 composite materials after reaction in-situ of phosphate with silver ions.The test and analysis results about composition,structure and morphology of composite material show that has a relatively fixed chemical structure,chemical composition,crystal and controllable morphology and interface.Photocatalytic evaluation results show that the activity of photocatalytic decomposition water to produce oxygen: The composite materials relative to pure silver phosphate materials to enhance more.（2）Based on the ultrasonic stripping technology,the lamellar molybdenum disulfide material with low structure was obtained,and it was effectively assembled with silver phosphate material to obtain the flaky molybdenum disulfide / silver phosphate composite;The grafted molybdenum disulfide / silver phosphate composite was prepared by means of hydrothermal synthesis,electrostatic driven self-assembly and in situ reaction.The scanning electronmicroscopy and transmission electron microscopy analysis show that:These composite material has both good composite microstructure and interfacial complex;The chemical composition,crystal structure and spectral test results show that the chemical composition of the composites is relatively fixed,the microstructure and the interface are controlled,effect of visible light absorption and utilization is well.Water splitting results show that:The visible light catalytic decomposition efficiency of composite material is much higher than that of pure silver phosphate.At the same time we compared flower or flake MoS₂/Ag3PO4 composite material on the performance of oxygen evolution,found that the flower composite is better than the flake composite.（3）We test free radicals of the samples in the visible light catalytic decomposition of water during the process by using electron spin resonance real-time,through the judgment of types and number of free radicals in the reaction process.In combination with other test results to analysis the main active group in the process of photocatalytic decomposition of water and introduce the reaction mechanism.