Selective Integrating Molecular Catalytic Units into Bipyridine-Based Covalent Organic Frameworks for Specific Photocatalytic Fuel Production

Abstract

Molecular metal compounds have demonstrated excellent catalytic activity and product selectivity in the H2 evolution reaction (HER) and the CO2 reduction reaction (CO2RR). The heterogenization of molecular catalysts is regarded as an effective approach to improve their applicability. In this work, the molecular catalytic units [Cp*Ir(Bpy)Cl]+ and [Ru(Bpy)(CO)2Cl2] are constructed in situ on the bipyridine sites of the covalent organic framework for photocatalytic HER and CO2RR, respectively. Inheriting the impressive performance of molecular catalysts, the functionalized TpBpy–M exhibits excellent catalytic activity and product selectivity. Under visible light irradiation, the H2 production rate of TpBpy–Ir is about 760 μmol g–1 h–1, which is 6.7 times higher than that of TpBpy without built-in catalytic sites. Also, the HCOOH production rate of TpBpy–Ru is 271 μmol g–1 h–1, with an impressive selectivity of 88%. Control experiments validated that this improvement is attributed to the incorporation of molecular catalytic units into the framework. Photoluminescence spectroscopy measurements and theoretical calculation consistently demonstrate that, under illumination, the photosensitizer [Ru(Bpy)3]Cl2 is excited and transfers electrons to the catalytic sites in TpBpy–M, which then catalyzes the reduction of H+ and CO2.

Bottom‐up Growth of Convex Sphere with Adjustable Cu(0)/Cu(I) Interfaces for Effective C2 Production from CO2 Electroreduction

“…The peak located at � 1625 cm À 1 attributed to the HCOO* species was just observed as the key reaction step for the formation of HCOOH in Cu NPs electrode (Figure 6c). [46][47][48][49] These findings agree with the product distribution that was found for each catalyst (Figure 4). Figure S19 showed the higher integrated intensities of the *CO band in Cu 0.25 @Cu 2 O convex sphere and its slower decay kinetics, confirming that *CO was more quickly and densely refilled in Cu 0.25 @Cu 2 O convex sphere than that of CuO/Cu 2 O smooth sphere and Cu NPs.…”

Cascade Electrocatalytic Reduction of Nitrate to Ammonia Using a Heterobimetallic Covalent Organic Framework Composed of Cu-Porphyrin and Co-Bipyridine

“…This characteristic peak is associated with coordination of pyridine N to cobalt ions. The shift toward higher binding energies is attributed to the reduced electron cloud density of N due to the bonding between N and Co 2+ . ,, …”

“…Due to the excellent porosity, high stability, and designable topology, covalent organic frameworks (COFs) serve as a powerful platform for immobilizing well-defined active sites for various catalyses. − However, a majority of the reported COFs contain only a single catalytic center, thereby limiting their efficacy in catalyzing complex multistep reactions and product selectivity. COFs with multiple catalytic centers offer distinct advantages in facilitating cascade reactions; however, there is a paucity of literature on this topic. − In this work, we demonstrate a COF-based electrocatalyst composed of copper porphyrin (CuP) and copper bipyridine (CoBpy) for the cascade catalysis of NO 3 – to NH 3 .…”