Metal-covalent organic frameworks for photocatalytic CO2 reduction: Mini review

Abstract

Advancements in global industrialization have led to over-reliance on fossil fuels, which has triggered a drastic surge in CO₂ emissions. This renders it imperative to develop renewable energy and efficient CO₂ conversion technologies. Among them, photocatalytic technology has garnered considerable interest due to its unique capacity to directly harness solar energy for converting CO₂ into value-added chemicals. Traditional inorganic semiconductor-based photocatalysts are plagued by inherent limitations including inadequate structural tunability and low product selectivity. In contrast, covalent organic frameworks (COFs) are crystalline porous materials that exhibit prominent merits such as structural tunability, high porosity and excellent stability, thus showing immense potential in photocatalytic CO₂ reduction. Furthermore, metal-covalent organic frameworks (MCOFs) through the introduction of metal sites synergistically integrate the advantages of COFs and metal organic frameworks (MOFs), thereby markedly boosting CO₂ adsorption and activation capabilities. The mini review systematically outlines the design and synthesis strategies of MCOFs and puts forward optimization methodologies from aspects including catalytic microenvironment modulation and molecular engineering, aiming to provide theoretical guidance for the development of the high-efficiency MCOF-based photocatalysts.