Palladium clusters confined in triazinyl-functionalized COFs with enhanced catalytic activity

Noble-metal-cluster-based catalysts have attracted immense research attention due to their high atom utilization ratio and superior catalytic activity. However, it is still challenging to control the size growth of noble-metal clusters. Here, triazinyl-functionalized covalent organic frameworks (Triazinyl-COFs) with different pore diameters were synthesized by the condensation of cyanuric chloride with each of p-phenylenediamine and 4,4′-diaminobiphenyl, referred to as COF-Ph and COF-BPh, respectively. A simple synthetic strategy was employed for controlling the Pd clusters growth and anchoring Pd clusters based on the confinement effect of Triazinyl-COFs pores. The as-obtained [email protected] and [email protected] catalysts with a Pd cluster size of ˜0.8 nm exhibited superior activity and excellent stability for the reduction of 4-nitrophenol, attributing to the high utilization of Pd active sites and the confinement effect of Triazinyl-COFs. Besides, the influence of the different pore sizes of COF-Ph and COF-BPh on the catalytic performance of the obtained catalysts was also investigated.