Rational Design of Covalent Cobaloxime–Covalent Organic Framework Hybrids for Enhanced Photocatalytic Hydrogen Evolution

Abstract

Covalent organic frameworks (COFs) display a unique combination of chemical tunability, structural diversity, high porosity, nanoscale regularity, and thermal stability. Recent efforts are directed at using such frameworks as tunable scaffolds for chemical reactions. In particular, COFs have emerged as viable platforms for mimicking natural photosynthesis. However, there is an indisputable need for efficient, stable, and economical alternatives for the traditional platinum-based cocatalysts for light-driven hydrogen evolution. Here, we present azide-functionalized chloro(pyridine)cobaloxime hydrogen-evolution cocatalysts immobilized on a hydrazone-based COF-42 backbone that show improved and prolonged photocatalytic activity with respect to equivalent physisorbed systems. Advanced solid-state NMR and quantum-chemical methods allow us to elucidate details of the improved photoreactivity and the structural composition of the involved active site. We found that a genuine interaction between the COF backbone and the cobaloxime facilitates recoordination of the cocatalyst during the photoreaction, thereby improving the reactivity and hindering degradation of the catalyst. The excellent stability and prolonged reactivity make the herein reported cobaloxime-tethered COF materials promising hydrogen evolution catalysts for future solar fuel technologies.

Nanoscale covalent organic frameworks as theranostic platforms for oncotherapy: synthesis, functionalization, and applications

“…Covalent post-SM based on a click reaction to form a triazole ring is an extremely versatile and efficient method that enables the development of custom-built COFs with tunable porosities and functionalities while maintaining their high crystallinity. 164,[290][291][292][293][294][295][296][297][298] The click reaction of vinyl with thiol is another typical clickchemistry-based post-SM method. For instance, vinylfunctionalized COF-V and 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecauorodecane-1-thiol with low surface free energy reacted in the presence of azobisisobutyronitrile (AIBN) as the catalyst to yield peruoroalkane-modied COF-VF ( Fig.…”

Quantifying the Likelihood of Structural Models through a Dynamically Enhanced Powder X‐Ray Diffraction Protocol

“…Thed esign of functional materials is instrumental for advancing technological solutions to tackle pressing societal problems, [1][2][3][4][5][6][7] such as combating climate change and creating clean energy pathways.I nt he last few years,n ew materials with particular functionalities have been proposed at av ery high pace,d ue to an in-depth microscopic understanding of their functionality and the growing toolbox of synthetic chemists.W ithin this toolbox lies the concept of reticular design, [8] where judiciously chosen building blocks are assembled in apredesigned topology,giving rise to materials such as metal-organic frameworks (MOFs) [9] and covalent organic frameworks (COFs). [10] Due to their extensive tailorability and attractiveness for av ast range of applications,t he structural design of MOFs and COFs has formed av ery active field of research.…”

Quantifying the Likelihood of Structural Models through a Dynamically Enhanced Powder X‐Ray Diffraction Protocol

“…Thed esign of functional materials is instrumental for advancing technological solutions to tackle pressing societal problems, [1][2][3][4][5][6][7] such as combating climate change and creating clean energy pathways.I nt he last few years,n ew materials with particular functionalities have been proposed at av ery high pace,d ue to an in-depth microscopic understanding of their functionality and the growing toolbox of synthetic chemists.W ithin this toolbox lies the concept of reticular design, [8] where judiciously chosen building blocks are assembled in apredesigned topology,giving rise to materials such as metal-organic frameworks (MOFs) [9] and covalent organic frameworks (COFs). [10] Due to their extensive tailorability and attractiveness for av ast range of applications,t he structural design of MOFs and COFs has formed av ery active field of research.…”

“…The design of functional materials is instrumental for advancing technological solutions to tackle pressing societal problems, [1–7] such as combating climate change and creating clean energy pathways. In the last few years, new materials with particular functionalities have been proposed at a very high pace, due to an in‐depth microscopic understanding of their functionality and the growing toolbox of synthetic chemists.…”