Modular Control of Local Electronic Structure for Tailoring Photothermal Responsiveness and Photocatalytic O2 Activation in Triazine-Based Covalent Organic Frameworks.

Abstract

In recent years, covalent organic frameworks (COFs) have revealed vast potential in photocatalysis and phototherapeutic applications, especially photodynamic therapy (PDT) and photothermal therapy (PTT), owing to their low risk of inducing resistance, broad-spectrum activity, non-invasive operation, and high efficiency. However, the modular control of their photothermal responsiveness and photocatalytic activity is under investigation. Here, we designed and synthesized two triazine-based COFs with distinct pore sizes and coordination microenvironments (TADA and TATP), and further incorporated atomically dispersed Cu sites into the materials (Cu-TADA and Cu-TATP) to finely modulate their electronic properties. The introduction of a few copper sites not only broadens the light-harvesting range of the materials, enhances charge separation and transfer, and photothermal responsiveness, but also modulates their oxygen-activation behaviors and reactive oxygen species (ROS) generation pathways, thereby leading to distinct light-enhanced antibacterial performances. These findings highlight a simple yet effective strategy for tailoring COFs from readily available monomers for modular photothermal performance and photocatalytic O2 activation and provide useful insights into the design of efficient and multifunctional COF antibacterial agents and photocatalysts.