Solar‐to‐H₂O₂ Catalyzed by Covalent Organic Frameworks

Abstract

Benefiting from the excellent structural tunability, robust framework, ultrahigh porosity, and rich active sites, covalent organic frameworks (COFs) are widely recognized as promising photocatalysts in chemical conversions, and emerged in the hydrogen peroxide (H2O2) photosynthesis from 2020. H2O2, serving as an environmental‐friendly oxidant and a promising liquid fuel, has attracted increasing researchers to explore its potential. Over the past few years, numerous COFs‐based photocatalysts are developed with encouraging achievements in H2O2 production, whereas no comprehensive review articles exist to summarize this specific and significant area. Herein we provide a systematic overview of the advances and challenges of COFs in photocatalytic H2O2 production. We first introduce the priorities of COFs in H2O2 photosynthesis. Then, various strategies to improve COFs photocatalytic efficiency are discussed. The perspective and outlook for future advances of COFs in this emerging field are finally offered. This timely review will pave the way for the development of highly efficient COFs photocatalysts for practical production of value‐added chemical not limited to H2O2.

Ionic Liquid‐Mediated Dynamic Polymerization for Facile Aqueous‐Phase Synthesis of Enzyme‐Covalent Organic Framework Biocatalysts

“…All the CB potentials were lower than the redox potential of O 2 /H 2 O 2 while all the valence bands (VB) were higher than the redox potential of H 2 O 2 /H 2 O, indicating that all TpBpy (HAc), TpBpy (IL), HRP@TpBpy (HAc) and HRP@TpBpy (IL) were thermodynamically favorable for the photosynthesis of H 2 O 2 from H 2 O and O 2 . Indeed, both TpBpy (IL) and TpBpy (HAc) frameworks showed the desirable photocatalytic synthesis of H 2 O 2 under xenon lamp irradiation (λ>400 nm; light intensity at 400–700 nm: 550 W m −2 ), and the ERP experiment demonstrated that ⋅OH and ⋅OOH were the main intermediate species participating in the generation of H 2 O 2 (Figure S51), well agreement with the previously reports [45–47,49] . Interestingly, based on the peroxidase chromogenic method for H 2 O 2 quantification (Figure S52), TpBpy (IL) exhibited 1.55‐fold H 2 O 2 production ability compared to TpBpy (HAc) (Figure 6c).…”

“…Crystalline COF skeleton means that the molecular tectons are orderly linked and this favors the formation of large π‐conjugated networks, holding attractive photoelectric attributes which cannot be attained in the amorphous polymer [45–47] . It is plausible that the spatial integration of enzymatic catalysis and the photoelectric effect of the COF skeleton in our enzyme@COF (IL) system may encourage new applications.…”

Boosting CO2 Photoreduction via Regulating Charge Transfer Ability in a One‐Dimensional Covalent Organic Framework

“…The thermogravimetric analysis results reveal that decomposition temperature of 1D PyTTA‐COF reaches 516 °C, which is significantly higher than that of 2D counterpart (486 °C, Figure S3). Meanwhile, 1D PyTTA‐COF displays good chemical stability, which can retain high crystallinity after immersing them in N,N‐Dimethylformamide (DMF), tetrahydrofuran (THF), dichloromethane (DCM), hydrochloric acid (HCl, pH=1), sodium hydroxide (NaOH, pH=13) for 24 h (Figure S3b) [46] …”

Imine-linked 2D covalent organic frameworks based on benzotrithiophene for visible-light-driven selective aerobic sulfoxidation

“…1–3 The abundant building units and various synthesis methods greatly enrich the diversity of COFs. 4–8 As potential materials, numerous applications including energy storage, 9–11 sensing, 12–14 adsorption, 15–18 and catalysis 19–23 have been developed based on COFs. Equipped with adjusted band positions and functionalized skeletons, COFs with inherent porosity are outstanding materials for efficient photocatalysis.…”