Research group of Professor lanyaqian of Nanjing Normal University: bifunctional crystalline covalent organic framework materials (COFS) for photoreduction of CO 2 in water

In the field of artificial light synthesis, it is still very challenging to realize the photocatalytic reduction of CO2 with water as sacrificial agent driven by visible light, especially the realization of this kind of reaction by crystal material catalyst Crystal materials with clear structure provide a good research platform for the theoretical study of photocatalysis, which can help us to better understand the photocatalytic reaction process, mechanism and structure-activity relationship with catalyst through visual structure, and also provide theoretical guidance for further development of efficient photocatalyst However, in addition to the well-known strategy of nano semiconductor heterojunction, how to select the appropriate structure components to assemble effective crystal photocatalysts to achieve this reaction is a very novel topic Recently, a series of COFS based on tetrathiafulvalene porphyrin have been designed and synthesized by Professor LAN Yaqian of Nanjing Normal University These crystalline materials can be used as electron donors for efficient CO 2 photoreduction without additional photosensitizers and sacrificial agents Driven by visible light, the COF catalyst realizes efficient electron hole separation and transfer between tetrathiafulvalene, an electron donor, and porphyrin, an electron acceptor (Fig 1), thus effectively connecting the reduction of CO2 at different sites with the half reaction of water oxidation This crystal structure model system will further deepen people's understanding of the relationship between the structure and function of photocatalyst At the same time, the density functional theory (DFT) calculation based on the accurate crystal structure model also confirms the rationality of the above theory Relevant research results were published in angelw Chem Int ed (DOI: 10.1002 / anie 201906890) Fig 1 introduction of Professor lanyaqian's research group since 2012 Since its establishment at the end of the year, the company has been mainly engaged in the research direction of cluster chemistry and coordination chemistry, designing and synthesizing novel and stable crystalline materials for the conversion and application of clean energy fields such as optical, electrical and chemical energy The research content involves the synthesis and application of POMs, MOCS, MOFs and COFS At present, the research group has made a series of important progress in the field of photocatalysis, including photodegradation of water, CO 2 reduction, oxygen reduction reaction (ORR), proton conduction and solid electrolyte materials More than 100 papers have been published in NAT Commun., J am Chem SOC., angelw Chem Int ed., adv mater., matter, chem SOC Rev And other internationally renowned journals At present, the research group has 3 postdoctors, 10 doctors and 12 masters Introduction to Professor LAN Yaqian, professor and doctoral supervisor of School of chemistry and materials, Nanjing Normal University Long term commitment to the application of crystalline materials in the field of energy exploration In 2009, he obtained a Ph.D in physical chemistry from Northeast Normal University, worked as a postdoctoral researcher in JSPS from 2010 to 2012, a special researcher for foreigners in Kansai center of AIST, and joined Nanjing Normal University at the end of 2012 After working independently, he was awarded the titles of the fourth batch of national "ten thousand talents plan" leading talents in science and technology innovation, the Ministry of education young Yangtze scholars award plan, the National Science Fund for outstanding young scholars, the leading talents of "innovation and entrepreneurship team" in Jiangsu Province, the outstanding youth fund of Jiangsu Province, the high-level talents of "innovation and entrepreneurship plan" in Jiangsu Province, and the distinguished professor of Jiangsu Province At present, he is a member of the academic committee of Nanjing Normal University and director of the professor committee of the school of chemistry and materials science He has won the third prize of natural science of Jilin Province (ranking first) Since I came to Nanjing Normal University, I have published more than 100 papers as a correspondent in NAT Commun., J am Chem SOC., angelw Chem Int ed., adv mater., matter, chem SOC Rev He cited more than 10000 papers, 16 papers highly cited by ESI, and personal h-index 55 Cutting edge scientific research achievements: bifunctional crystalline covalent organic framework materials (COFS) realize the photoreduction of CO 2 in water in the field of artificial light synthesis It is still very challenging to realize the catalytic CO 2 photoreduction and water oxidation (i.e water as sacrificial agent) under the driving of visible light Recently, a series of novel crystal covalent organic framework (COFS) catalysts ttcof-m (Fig 2) with tetrathiafulvalene porphyrin as the structural unit have been designed and synthesized by the research group of Professor lanyaqian of Nanjing Normal University in order to realize such reactions Fig 2 Synthesis and structural characterization of ttcof-m (source: angel Chem Int ed.) first, the morphology and optical characterization of the synthesized crystalline COF material were tested by the author (Fig 3) It is worth noting that in this catalyst, the band gap of COF material is regulated by adjusting the type of porphyrin central metal It is found that ttcof Zn / Cu has a suitable position of conduction band and valence band (Fig 3f), which can theoretically match the requirements of CO 2 reduction and water oxidation Figure 3 Morphology and optical characterization of ttcof (source: angel Chem Int ed.) with COF as catalyst, the photocatalytic test was carried out in CO2 saturated water phase under visible light (420-800 nm) (without adding additional photosensitizers and electron sacrificial agents) Figure 4 shows the photo reduction performance of ttcof material, in which ttcof Zn can convert CO2 into CO under the experimental conditions, with nearly 100% selectivity, and the co output reaches 12.33 μ mol after 60 hours At the same time, water as electron donor produces oxygen by water oxidation Figure 4 Photocatalytic performance of ttcof-m (source: angel Chem Int ed.) in addition, the photocatalytic mechanism of ttcof-m material is also discussed in this paper It is suggested that the efficient electron hole separation and electron transfer from tetrathiafulvalene to acceptor porphyrin is the main reason for the reduction of CO2 in water It is suggested that the reduction of CO 2 occurs in the center of the negatively charged porphyrin, while the oxidation of water occurs in the center of tetrathiafulvalene with a large number of positive holes Moreover, the above theory is confirmed by DFT calculation results based on crystal structure model (Figure 5) Figure 5 Mechanism of CO 2 reduction reaction (source: angelw Chem Int ed.) To sum up, this work creatively designed and synthesized a kind of crystal COF for photoreduction of CO 2 with water as electron donor The catalyst system also provides an important case study and a new strategy for the development of efficient and stable crystalline photocatalysts for artificial photosynthesis Under the guidance of Professor LAN Yaqian of the research group, the experimental design and writing of the research work were jointly completed by Lu Meng, a doctoral student, and Liu Jiang, an associate professor The experimental part was jointly completed by Lu Meng, Zhang Mi, and Liu Ming, a master student The theoretical calculation part was completed by Li Qiang, a teacher of Southeast University Thanks to researcher yuan Daqiang of Fujian Institute of material structure, Chinese Academy of Sciences for his strong support in crystal structure analysis The research work was supported by the National Natural Science Foundation of China (No 21622104, 21471080, 2170010097 and 21701085, bk20171032) and the natural science foundation of Jiangsu Province (No sbk2017040708) Nowadays, people and scientific research have been paid more and more attention in the economic life China has ushered in the "node of science and technology explosion" Behind the progress of science and technology is the work of countless scientists In the field of chemistry, in the context of the pursuit of innovation driven, international cooperation has been strengthened, the influence of Returned Scholars in the field of R & D has become increasingly prominent, and many excellent research groups have emerged in China For this reason, CBG information adopts the 1 + X reporting mechanism CBG information, chembeangoapp, chembeango official microblog, CBG wechat subscription number and other platforms jointly launch the column of "people and scientific research", approach the domestic representative research group, pay attention to their research, listen to their stories, record their demeanor, and explore their scientific research spirit.