Two-dimensional conductive metal–organic framework with 2,3,6,7,14,15-triptycenehexathiol (TCHT) ligand: synthesis, structure, electrical conductivity and CO2RR activity

Abstract

Two-dimensional conductive metal–organic frameworks (2D-c-MOFs) are promising materials for applications in electrochemical devices. However, the metal sites in most 2D-c-MOFs are typically inaccessible because of π–π stacking between the 2D sheets. In contrast, 2D-c-MOFs in which the conjugated π-planes of the ligands are oriented perpendicular to the 2D sheets (“vertical ligands”) can offer improved guest accessibility to the metal sites. Here, we report the synthesis of a novel vertical ligand, 2,3,6,7,14,15-triptycenehexathiol (TCHT), and its corresponding 2D-c-MOF, Cu-TCHT. Powder X-ray diffraction (PXRD) patterns suggested its honeycomb structure. Furthermore, electrochemical catalytic activity for the CO₂ reduction reaction (CO₂RR) was improved over conventional 2D-c-MOF with horizontal ligands (Cu-BHT) probably because the porous honeycomb structure with the vertical ligands facilitates access to the metal sites.