Green synthesis of bifunctional phthalocyanine-porphyrin cofs in water for efficient electrocatalytic CO2 reduction coupled with methanol oxidation

Mi Zhang; Jia-Peng Liao; Run-Han Li; Sheng-Nan Sun; Meng Lu; Long-Zhang Dong; Pei Huang; Shun-Li Li; Yue-Peng Cai; Ya-Qian Lan

doi:10.1093/nsr/nwad226

Green synthesis of bifunctional phthalocyanine-porphyrin cofs in water for efficient electrocatalytic CO₂ reduction coupled with methanol oxidation

Natl Sci Rev. 2023 Sep 2;10(11):nwad226. doi: 10.1093/nsr/nwad226. eCollection 2023 Nov.

Authors

Affiliation

¹ School of Chemistry, South China Normal University, Guangzhou510006, China.

Abstract

Electrocatalytic CO₂ reduction (ECR) coupled with organic oxidation is a promising strategy to produce high value-added chemicals and improve energy efficiency. However, achieving the efficient redox coupling reaction is still challenging due to the lack of suitable electrocatalysts. Herein, we designed two bifunctional polyimides-linked covalent organic frameworks (PI-COFs) through assembling phthalocyanine (Pc) and porphyrin (Por) by non-toxic hydrothermal methods in pure water to realize the above catalytic reactions. Due to the high conductivity and well-defined active sites with different chemical environments, NiPc-NiPor COF performs efficient ECR coupled with methanol oxidation reaction (MOR) (Faradaic efficiency of CO (FE_CO) = 98.12%, partial current densities of CO (j_CO) = 6.14 mA cm^-2 for ECR, FE_HCOOH = 93.75%, j_HCOOH = 5.81 mA cm^-2 for MOR at low cell voltage (2.1 V) and remarkable long-term stability). Furthermore, experimental evidences and density functional theory (DFT) calculations demonstrate that the ECR process mainly conducts on NiPc unit with the assistance of NiPor, meanwhile, the MOR prefers NiPor conjugating with NiPc. The two units of NiPc-NiPor COF collaboratively promote the coupled oxidation-reduction reaction. For the first time, this work achieves the rational design of bifunctional COFs for coupled heterogeneous catalysis, which opens a new area for crystalline material catalysts.

Keywords: bifunctional electrocatalysts; electrocatalytic CO2 reduction; hydrothermal synthesis; methanol oxidation reaction; phthalocyanine-porphyrin COFs.