Metallated Isoindigo-Porphyrin Covalent Organic Framework Photocatalyst with a Narrow Band Gap for Efficient CO2Conversion

Tina Skorjanc, Dinesh Shetty, Mahmoud Elcheikh Mahmoud, Felipe Gándara, Jose Ignacio Martinez, Abdul Khayum Mohammed, Sandra Boutros, Areej Merhi, Elissa O. Shehayeb, Christa A. Sharabati, Patrick Damacet, Jesus Raya, Sandra Gardonio, Mohamad Hmadeh, Bilal R. Kaafarani, Ali Trabolsi

Research output: Contribution to journalArticlepeer-review


Photocatalytic CO2 reduction into formate (HCOO-) has been widely studied with semiconductor and molecule-based systems, but it is rarely investigated with covalent organic frameworks (COFs). Herein, we report a novel donor-acceptor COF named Co-PI-COF composed of isoindigo and metallated porphyrin subunits that exhibits high catalytic efficiency (∼50 μmol formate g-1 h-1) at low-power visible-light irradiation and in the absence of rare metal cocatalysts. Density functional theory calculations and experimental diffuse-reflectance measurements are used to explain the origin of catalytic efficiency and the particularly low band gap (0.56 eV) in this material. The mechanism of photocatalysis is also studied experimentally and is found to involve electron transfer from the sacrificial agent to the excited Co-PI-COF. The observed high-efficiency conversion could be ascribed to the enhanced CO2 adsorption on the coordinatively unsaturated cobalt centers, the narrow band gap, and the efficient transfer of the charge originating from the postsynthetic metallation. It is anticipated that this study will pave the way toward the design of new simple and efficient catalysts for photocatalytic CO2 reduction into useful products.

Original languageEnglish (US)
Pages (from-to)2015-2022
Number of pages8
JournalACS Applied Materials and Interfaces
Issue number1
StatePublished - Jan 12 2022


  • COreduction
  • covalent organic frameworks
  • formate
  • isoindigo
  • photocatalysis

ASJC Scopus subject areas

  • General Materials Science


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