Nickel Glyoximate Based Metal–Covalent Organic Frameworks for Efficient Photocatalytic Hydrogen Evolution

Abstract

Metal-covalent organic frameworks (MCOFs) have been recently received wide attention owing to the homogeneous distribution of active metal centers that are beneficial for enhancing the application potentials. However, metal complex based functional building blocks for MCOFs synthesis are limited. Herein, two new MCOFs (Ni-Py-COF and Ni-Bn-COF) were constructed via a novel nickel glyoximate based building block. Splendid photocatalytic activity on hydrogen evolution from water and great long-term recyclability were achieved using these nickel glyoximate based MCOFs as photocatalysts. Excitingly, even without the addition of Pt co-catalyst, the hydrogen evolution rates (HER) of Ni-Py-COF reached up to 626 μmol g À 1 h À 1 , which is better than many porous organic polymers. This work not only expands the type of building units for MCOFs, but also provides meaningful insights for developing stable, efficient and earth-abundant photocatalysts toward H 2 generation.Covalent organic frameworks (COFs), as a promising class of porous crystalline polymers, have demonstrated considerable advantages and application potential in various fields owing to designable structures and tailor-made functions. [1] C, H, N and other light elements constituted the majority of COFs namely metal-free COFs. [2] However, most metal-free COFs fail to exhibit versatile and outstanding properties due to their limited constituent elements. [3] Recently, a new class of COFs with intentionally integrated metal centers into the skeletons are considered as promising candidates to address this dilemma; these are referred to as metal-covalent organic frameworks (MCOFs). [4] MCOFs not only inherit

Integrated Photothermal Nanoreactors for Efficient Hydrogenation of CO2

“…The key to the controlled preparation of the IPR is the encapsulation of ZIF-67 nanocrystals within a silica sheath to realize the discontinuous size distribution [28][29][30][31]. Silica sheath provides the anchoring effect for Co cations at the SiO 2 / ZIF-67 interface, further suppressing the sintering of Co satellites during the pretreatment.…”

Superhydrophilic covalent organic frameworks accelerate photocatalytic production of hydrogen peroxide through proton channels

“…19 Therefore, key factors in increasing H 2 O 2 yield lie in promoting light utilization and enhancing the hydrophilicity of photocatalysts. 20,21 Concerning electrons, the modulation of COFs generally focuses on structural aspects to expedite the separation of electron–hole pairs. Constructing electron donor–acceptor (D–A) systems is considered a widespread and effective strategy to reduce the recombination of photogenerated charge carriers due to their molecular diversity, functionalization potential, and tunable electronic configurations.…”

Chemical conversion of metal–organic frameworks into hemi-covalent organic frameworks

“…On the one hand, few metal complexes have been used as building blocks in the direct synthesis of MCOFs. 35,46,47 On the other hand, in comparison with metal free molecules, the employment of some metal complexes such as porphyrin leads to only poorly crystalline and amorphous materials. 48,49 New approaches towards designing and fabricating MCOFs are therefore highly desired for the purpose of affording more functional reticular materials.…”