Single Ru Sites on Covalent Organic Framework‐Coated Carbon Nanotubes for Highly Efficient Electrocatalytic Hydrogen Evolution

Abstract

Covalent organic frameworks (COFs) with precisely controllable structures and highly ordered porosity possess great potential as electrocatalysts for hydrogen evolution reaction (HER). However, the catalytic performance of pristine COFs is limited by the poor active sites and low electron transfer. Herein, to address these issues, the conductive carbon nanotubes (CNTs) are coated by a defined structure RuBpy(H2O)(OH)Cl2 in bipyridine‐based COF (TpBpy). And this composite with single site Ru incorporated can be used as HER electrocatalyst in alkaline conditions. A series of crucial issues are carefully discussed through experiments and density functional theory (DFT) calculations, such as the coordination structure of the atomically dispersion Ru ions, the catalytic mechanism of the embedded catalytic site, and the effect of COF and CNTs on the electrocatalytic properties. According to DFT calculations, the embedded single sites Ru act as catalytic sites for H2 generation. Benefitting from increasing the catalyst conductivity and the charge transfer, the as‐prepared c‐CNT‐0.68@TpBpy‐Ru shows an excellent HER overpotential of 112 mV at 10 mA cm−2 under alkaline conditions as well as an excellent durability up to 12 h, which is superior to that of most of the reported COFs electrocatalysts in alkaline solution.

Chiral Ru-Based Covalent Organic Frameworks as An Electrochemiluminescence-Active Platform for the Enantioselective Sensing of Amino Acids

“…In addition, the high-resolution C 1s spectrum of Ru­(bpy)­( S -CHDA) 2 2+ can be divided into two peaks: 283.3 and 284.2 eV, which are assigned to the C–C/CC and CN–C bonds (Figure E). , The imine nitrogen is also shown in the high-resolution N 1s spectrum at 397.9 eV (Figure F). More importantly, the N–Ru bond emerges at 398.9 eV, , pointing to the coordination among Bpy-COF, Ru 2+ , and ( S )–CHDA.…”

Recent Advances of Covalent Organic Frameworks as Water Splitting Electrocatalysts

“…Meanwhile, adopting a similar strategy, Wang and team reported an elegant strategy by grafting the ruthenium (Ru)-modified bipyridine-based COF (TpBpy-Ru) on carboxyl-functionalized carbon nanotubes (c-CNTs), thus enhancing the electron transfer capacity (Figure 3f). 39 The c-CNT@TpBpy was firstly prepared via mechanochemical grinding and further immobilizing the Ru precursor at room temperature. Such a synthetic strategy combines the welldispersed HER active Ru species on TpBpy pores and enhanced the electron transfer capacity of the c-CNT@TpBpy composite.…”

“…(f) Synthesis route for c-CNT@TpBpy-Ru HER electrocatalyst. Reproduced with permission 40. Copyright 2023, Wiley-VCH.…”

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

“…COFs containing the 2,2′-bipyridine (Bpy) unit offer an optimal platform for postmetal functionalization. , Meanwhile, Bpy is a widely employed ligand in coordination chemistry, and a range of metal complexes containing bipyridine ligands have been discovered to be highly effective molecular catalysts for HER and CO 2 RR. For instance, [Cp*Ir­(Bpy)­Cl]Cl has demonstrated remarkable photoelectrocatalytic performance for H 2 evolution in aqueous solution .…”