Cofacial porphyrin organic cages. Metals regulating excitation electron transfer and CO2 reduction electrocatalytic properties

Xiaolin Liu; Chenxi Liu; Xiaojuan Song; Xu Ding; Hailong Wang; Baoqiu Yu; Heyuan Liu; Bin Han; Xiyou Li; Jianzhuang Jiang

doi:10.1039/d3sc01816d

Cofacial porphyrin organic cages. Metals regulating excitation electron transfer and CO₂ reduction electrocatalytic properties

Chem Sci. 2023 Aug 10;14(34):9086-9094. doi: 10.1039/d3sc01816d. eCollection 2023 Aug 30.

Authors

Affiliations

¹ Beijing Advanced Innovation Center for Materials Genome Engineering, Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, Department of Chemistry and Chemical Engineering, School of Chemistry and Biological Engineering University of Science and Technology Beijing Beijing 100083 China hlwang@ustb.edu.cn jianzhuang@ustb.edu.cn.
² School of Materials Science and Engineering China University of Petroleum (East China) Qingdao 266580 China 20170053@upc.edu.cn xiyouli@upc.edu.cn.

Abstract

Herein, we introduce a comprehensive study of the photophysical behaviors and CO₂ reduction electrocatalytic properties of a series of cofacial porphyrin organic cages (CPOC-M, M = H₂, Co(ii), Ni(ii), Cu(ii), Zn(ii)), which are constructed by the covalent-bonded self-assembly of 5,10,15,20-tetrakis(4-formylphenyl)porphyrin (TFPP) and chiral (2-aminocyclohexyl)-1,4,5,8-naphthalenetetraformyl diimide (ANDI), followed by post-synthetic metalation. Electronic coupling between the TFPP donor and naphthalene-1,4 : 5,8-bis(dicarboximide) (NDI) acceptor in the metal-free cage is revealed to be very weak by UV-vis spectroscopic, electrochemical, and theoretical investigations. Photoexcitation of CPOC-H₂, as well as its post-synthetic Zn and Co counterparts, leads to fast energy transfer from the triplet state porphyrin to the NDI unit according to the femtosecond transient absorption spectroscopic results. In addition, CPOC-Co enables much better electrocatalytic activity for CO₂ reduction reaction than the other metallic CPOC-M (M = Ni(ii), Cu(ii), Zn(ii)) and monomeric porphyrin cobalt compartment, supplying a partial current density of 18.0 mA cm^-2 at -0.90 V with 90% faradaic efficiency of CO.