Demystifying the roles of single metal site and cluster in CO2 reduction via light and electric dual-responsive polyoxometalate-based metal-organic frameworks

• Published in: Science advances 2022-12, Vol.8 (49), p.eadd5598-eadd5598
• Main Authors: Huang, Qing, Niu, Qian, Li, Xiu-Fen, Liu, Jiang, Sun, Sheng-Nan, Dong, Long-Zhang, Li, Shun-Li, Cai, Yue-Peng, Lan, Ya-Qian
• Format: Article
• Language: English
• Subjects: Chemistry; Electrochemistry; Physical and Materials Sciences; SciAdv r-articles
• ISSN: 2375-2548
• DOI: 10.1126/sciadv.add5598

Photo- or electroreduction of carbon dioxide into highly valued products offers a promising strategy to achieve carbon neutrality. Here, a series of polyoxometalate-based metal-organic frameworks (M-POMOFs) were constructed by metalloporphyrins [tetrakis(4-carboxyphenyl)-porphyrin-M (M-TCPPs)] and reductive POM for photo- and electrocatalytic carbon dioxide reductions (PCR and ECR, respectively), and the mysteries between the roles of single metal site and cluster in catalysis were disclosed. Iron-POMOF exhibited an excellent selectivity (97.2%) with high methane production of 922 micromoles per gram in PCR, together with superior Faradaic efficiency for carbon dioxide to carbon monoxide (92.1%) in ECR. The underlying mechanisms were further clarified. Photogenerated electrons transferred from iron-TCPP to the POM cluster for methane generation under irradiation, while the abundant electrons flowed to the center of iron-TCPP for carbon monoxide formation under the applied electric field. The specific multielectron products generated on iron-POMOF through switching driving forces to control electron flow direction between single metal site and cluster catalysis.