Assembly of two trinuclear-cluster-based metal-organic frameworks: Structures and methanol electro-oxidation properties

Abstract

The direct methanol fuel cell (DMFC) is an efficient and non-polluting green energy conversion device. However, the electrocatalysts for the anodic methanol oxidation reaction (MOR) in DMFC are often precious metal catalysts, which suffer from high cost, poor stability, and easy deactivation. In this work, two isostructural metal-organic frameworks (MOFs) [M3(μ3-OH)(TATB)(Nic)2(H2O)2(DMA)] (M = Co, Ni) were successfully synthesized under solvothermal conditions. Both frameworks possess a unique trinuclear cluster [M3(μ3-OH)(COO)5] secondary building unit (SBU) and a rare binodal (3,7)-connected network. Due to the high density of metal sites and prominent pore system within CTGU-36-Ni, it can serve as an effective molecular electrocatalyst for MOR, while CTGU-36-Co is an inert material. Further experimental results showed that the introduction of conductive substances could lead to a significant increase in the MOR area activity of CTGU-36-Ni. This work not only provides a non-noble metal molecular MOR electrocatalyst but also opens a new vision for the design and application of crystalline materials in various energy conversion processes.