Two-dimensional conductive MOF has excellent conductivity and structural stability

In recent years, the use of electricity generated by renewable energy sources to reduce CO ₂ electricity to various high value-added chemicals is a promising path to achieve carbon balance, which has attracted wide attention from researchers
.

At present, most non-precious metal catalysts use the carbon-based materials obtained by pyrolyzing the precursors in electrocatalysis, but they have the problems of complex active components and uneven distribution

Recently, researcher Cao Rong and researcher Huang Yuanbiao of the Fujian Institute of the Structure of Matter of the Chinese Academy of Sciences used nickel phthalocyanine molecules with a macrocyclic conjugated structure as the basic building block to synthesize a two-dimensional conductive MOF (Figure 1), which has excellent electrical conductivity.
Sexuality and structural stability
.

The CO ₂ electro-reduction performance was tested in the water medium of the H-type electrolytic cell , and it was found that it can efficiently convert CO ₂ into CO, with a selectivity of up to 98.

Figure 1.
Schematic diagram of conductive MOF synthesis and basic characterization

A nickel octahydroxyphthalocyanine molecule with a macrocyclic conjugated structure was selected as the ligand, and a two-dimensional conductive MOF was synthesized by solvothermal method
.

After ultrasonic peeling, ultra-thin two-dimensional nanosheets can be obtained.

By comparing the PXRD and XPS spectra of the catalyst before and after the reaction, as well as the synchrotron radiation X-ray absorption spectrum fitting and wavelet transform, the change process of the coordination model of the node in the electrocatalytic process is analyzed
.

It is proved that after the electrocatalytic process, the structure of MOFs is still well maintained, which proves that the material has excellent structural stability

Through theoretical calculation analysis and designing control experiments, it is proved that the Ni atom in the center of the phthalocyanine is the catalytically active site
.

At the same time, by analyzing the charge distribution, CO ₂ adsorption capacity and reducibility of the Ni catalytic site in the phthalocyanine center , the reason why the material has such a highly efficient catalytic activity is explained

Figure 2.
CO ₂ electro-reduction performance test of the catalyst

This work shows that crystalline materials can also achieve high-efficiency electrocatalytic activity and structural stability
.

At the same time, by introducing phthalocyanine molecules with high catalytic activity into the porous crystalline material, a bridge is built between the homogeneous molecular catalyst and the heterogeneous porous catalyst, and a new type of high-density active site and active site is designed for the subsequent design.

This result was recently published in Angewandte Chemie International Edition.