Recently, the research group led by Prof. Yaqian Lan from the School of Chemistry and Material Science of NNU has achieved significant progress in their study on exploring a crystalline photocatalytic system with a well-defined structure to accomplish an artificial photosynthetic overall reaction. Their results were published in Angew. Chem. Int. Ed., titled “Stable Heterometallic Cluster‐Based Organic Frameworks Catalysts for Artificial Photosynthesis”. Angew. Chem. Int. Ed., published by Wiley-VCH, is one of the most prestigious chemistry journals in the world.
In recent years, increasing anthropogenic CO2 emissions have caused severe energy and environmental issues. In response to these problems, most research has concentrated on exploring effective ways to achieve the artificial conversion of CO2. However, considering the inherent chemical inertness of CO2 and its slow reaction kinetics, effective combination of CO2 reduction and H2O oxidation half-reactions (i.e. overall reaction) in one photocatalytic system is still daunting work. At present, the overall reaction could be achieved by a few nanostructured photocatalysts such as Z-scheme heterojunctions. However, because of the influences of defects, impure phases and complicated structural components, there is still lack of sufficient and clear structural information to identify the specific catalytic sites in these catalysts. Thus, exploring a crystalline photocatalytic system with a well-defined structure is considered as one of the most promising choices to address these issues.
In the paper, a series of stable heterometallic Fe2M cluster‐based MOFs (NNU‐31‐M, M=Co, Ni, Zn) photocatalysts are presented. They can achieve the overall conversion of CO2 and H2O into HCOOH and O2 without the assistance of an additional sacrificial agent and photosensitizer. The heterometallic cluster units and photosensitive ligands excited by visible light generate separated electrons and holes. Then, low‐valent metal M accepts electrons to reduce CO2, and high‐valent Fe uses holes to oxidize H2O.
This is the first MOF photocatalyst system to accomplish an artificial photosynthetic full reaction. It is noted that NNU‐31‐Zn exhibits the highest HCOOH yield of 26.3 μmol g−1 h−1 (selectivity of ca. 100 %). Furthermore, the DFT calculations based on crystal structures demonstrate the photocatalytic reaction mechanism.
This work proposes a new strategy for how to design crystalline photocatalyst to accomplish an artificial photosynthetic overall reaction.
PhD. candidate Longzhang Dong from the School of Chemistry and Material Sciences of NNU is the first author of the paper and Prof. Yaqian Lan and Associate Professor Jiang Liu are co-corresponding authors.