The research group led by Prof. Yaqian Lan from the School of Chemistry and Material Sciences at NNU recently has made significant achievements in providing a new insight for designing more efficient artificial crystalline photocatalysts and published a paper in the leading journal Angew. Chem. Int. Ed., titled Rational Design of Crystalline Covalent Organic Frameworks for Efficient CO2Photoreduction with H2O.
Solar energy‐driven conversion of CO2 into fuels with H2O as a sacrificial agent is a challenging research field in photosynthesis. Artificial photosynthesis is expected to mimic the above‐mentioned process efficiently for reducing CO2 with H2O as an electron donor, that is, integrating the CO2 reduction reaction (CO2RR) and H2O oxidation half‐reactions in one catalytic system, in which the development of photocatalysts is the most crucial factor. However, it is daunting work to enable these two half‐reactions to couple and interact effectively. At present, only very limited strategies on the design of efficient photocatalysts can realize the overall reaction, such as Z‐scheme heterojunctions, which still face many problems.
The NNU research team synthesized a series of crystalline porphyrin‐tetrathiafulvalene covalent organic frameworks (COFs) used as photocatalysts for reducing CO2 with H2O, in the absence of an additional photosensitizer, sacrificial agents, and noble metal co‐catalysts. The effective photogenerated electrons transfer from tetrathiafulvalene to porphyrin by covalent bonding, resulted in the separated electrons and holes, respectively, for CO2 reduction and H2O oxidation. By adjusting the band structures of TTCOFs, TTCOF‐Zn achieved the highest photocatalytic CO production of 12.33 μmol with circa 100 % selectivity, along with H2O oxidation to O2. Furthermore, DFT calculations combined with a crystal structure model confirmed the structure–function relationship.
This is the first report of a rationally designed crystalline COF system applied for the selective photoreduction of CO2 with H2O as an electron donor. Moreover, they offer a more straightforward and clearer crystalline evidence for understanding the structure–function relationship of heterogeneous photocatalysts. Their research provides a new insight into the design of next generation crystalline photocatalysts for artificial photosynthesis of CO2 with H2O.
Prof. Yaqian Lan is the corresponding author. Ph.D student Meng Lu and associate professor Jiang Liu from the School of Chemistry and Material Sciences at NNU are joint first authors.