The effect of enantioselective chiral covalent organic frameworks and cysteine sacrificial donors on photocatalytic hydrogen evolution

Abstract

Covalent organic frameworks (COFs) have constituted an emerging class of organic photocatalysts showing enormous potential for visible photocatalytic H2 evolution from water. However, suffering from sluggish reaction kinetics, COFs often cooperate with precious metal co-catalysts for essential proton-reducing capability. Here, we synthesize a chiral β-ketoenamine-linked COF coordinated with 10.51 wt% of atomically dispersed Cu(II) as an electron transfer mediator. The enantioselective combination of the chiral COF-Cu(II) skeleton with L-/D-cysteine sacrificial donors remarkably strengthens the hole extraction kinetics, and in turn, the photoinduced electrons accumulate and rapidly transfer via the coordinated Cu ions. Also, the parallelly stacking sequence of chiral COFs provides the energetically favorable arrangement for the H-adsorbed sites. Thus, without precious metal, the visible photocatalytic H2 evolution rate reaches as high as 14.72 mmol h−1 g−1 for the enantiomeric mixtures. This study opens up a strategy for optimizing the reaction kinetics and promises the exciting potential of chiral COFs for photocatalysis.

Modulating Electrochemical CO2 Reduction Performance via Sulfur-Containing Linkages Engineering in Metallophthalocyanine Based Covalent Organic Frameworks

“…The performance FE CO of CoPc-DSDS-COF catalysts at 10 mA cm –2 current density is better than that of most COF catalysts reported so far, such as COF-Co-366 (FE CO 90%) 4 , COF-Co-367 (FE CO 91%) 4 , Co-TTCOF (FE CO 91.3%) and CuPcF8-CoPc-COF (FE CO 91%) . CoPc-DSDS-COF and CoPc-DNDS-COF delivered the highest j CO values of 30.42 and 19.6 mA cm –2 at −1.0 V (Figure S17 red and blue curves).…”

“…Covalent organic frameworks (COFs) are an emerging class of crystalline porous material with structural regularity, simple accessibility, chemical stability, and built-in functional tunability at the molecular level. − To date, many COFs have been synthesized and have shown great potential for applications in various fields such as gas separation and storage, optoelectronics, − energy storage, − and catalysis. − Among all COFs, owing to the photosensitive 18π aromatic macrocyclic nature of MPc, constructing COFs with MPc units provides an opportunity for the development of electrochemical materials and has recently become a hot research topic. − In 2021, two novel pyrazine (pz)-linked metal-phthalocyanine (MPc)-based conjugated 2D COFs were constructed by the Feng group . Most relevantly, Jiang et al reported that phenazine-linked Co-phthalocyanine COFs (CoPc-PDQ-COFs) with high stability and conductivity were used as efficient electrocatalysts for the CO 2 RR .…”

A Fluorinated Covalent Organic Framework with Accelerated Oxygen Transfer Nanochannels for High‐Performance Zinc–Air Batteries

“…By contrast, pore-forming materials were regarded as one brilliant choice to improve mass transfer. [43,44] covalent organic frameworks (COFs), [45] an emerging material with regular pores and good crystallinity, are widely used in catalysis, energy conversion, and gas storage, [46][47][48][49][50] and it is constructed by light elements through covalent bonds, which has the advantages of higher stability and lower density than the metal-organic frameworks that formed by coordination of metal ions or clusters with organic ligands. Moreover, COFs are composed of topologically connected organic building units, [51,52] functional groupsThe establishment of abundant three-phase interfaces with accelerated mass transfer in air cathodes is highly desirable for the development of high-rate and long-cycling rechargeable zinc-air batteries (ZABs).…”

Pd nanoparticle-decorated covalent organic frameworks for enhanced photocatalytic tetracycline hydrochloride degradation and hydrogen evolution

“…For instance, Pt-coordinated imine-linked COFs or alkene-linked COFs show good photocatalytic performance. [13][14][15] However, COFs still suffer from an amorphous structure and chemical instability. COFs synthesized by Schiff base reaction or boronic acid dehydration reaction can achieve high crystallinity at the expense of charge carrier mobility, due to poor electron delocalization caused by the strongly polarized nature of the dynamic covalent bonds.…”

“…For instance, Pt-coordinated imine-linked COFs or alkene-linked COFs show good photocatalytic performance. 13–15…”