Recently, Prof. Xiong Yujie of the University of Science and Technology of China, in collaboration with Prof. Jiang Jun and Prof. Zhang Qun, has achieved a series of advancements in the design of photocatalytic composite materials through cooperation with the “three-point integration†in materials design and synthesis, theoretical simulation, and advanced characterization. The latest research progress was published on Advanced Materials, published on July 23. Two papers were presented in the journal's inner cover and inner back cover respectively. The co-first authors of the two work were Ph.D. students Bo Xi and Ge Jing, Li Rui, and Hu Jiahua.
As we all know, the development and application of functional materials has encountered a serious bottleneck at the present stage, and the single material system has been unable to break through the limitations of performance and meet the needs of the application field. Each specific material generally has unique properties and advantages in a certain aspect. The compounding of materials is an effective way to break the performance bottleneck of a single material, and it is hoped that the respective performance can be enhanced by the synergy between the composite elements (that is, 1+1>2). .
Specific to the photocatalytic system, different constituent elements in the composite material can play various important roles such as generating and separating charges, adsorbing activated molecules, and the like. However, in fact, the performance of composite materials is often difficult to achieve the superposition of their respective properties. The key bottleneck is that the structure of the interface of the composite system is very difficult to control, which leads to serious recombination and great waste of photogenerated charges on the interface.
For this bottleneck, researchers designed a series of composite structure systems with controllable interfaces. For example, for the first time, a semiconductor-metal-graphene stack structure has been proposed. The single crystal interface solves the problem of electron-hole recombination at the interface to a certain degree, and can make good use of the Schottky barrier between the semiconductor and the metal. The semiconductor photogenerated electron-hole pair separation is improved, thereby exhibiting significantly improved performance in photocatalytic hydrogen production.
On the other hand, aiming at the problem that gas molecules cannot be captured simultaneously in a specific gas phase photocatalytic reaction, a class of metal-organic framework (MOF)-semiconductor core-shell structures are designed. The photoelectron in the semiconductor can be effectively transferred to the MOF core and has a very good Long exciton life, but the carbon dioxide molecules adsorbed on the MOF core are converted to methane after photoelectron gain, thereby increasing the activity and selectivity of the carbon dioxide conversion fuel reaction. In the research, ultra-fast spectroscopic and kinetic characterization and theoretical simulations all confirmed the superiority of photocatalysis of the designed composite material system and revealed the microscopic mechanism of action. This series of researches is helpful to deepen people's understanding of the behavior and mechanism of photogenerated charge in composite structure materials, and it also plays an important role in the rational design of composite structure photocatalysts.
The above research work has been funded by the Ministry of Science and Technology's "973" program, the National Natural Science Foundation, the National Youth 1000 Program, the Chinese Academy of Sciences 100-person plan, the Chinese Academy of Sciences pilot project, and China University of Science and Technology major project training fund.
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