Covalent Organic Frameworks with Molecular Electronic Modulation as Metal‐Free Electrocatalysts for Efficient Hydrogen Peroxide Production

Abstract

Tuning the electronic property of active center to balance the adsorption ability and reactivity of oxygen is essential for achieving 2e− oxygen reduction reaction (ORR) for electrocatalytic synthesis of hydrogen peroxide (H2O2), still represents a grand challenge. Herein, different by‐design building blocks are introduced to regulate the electronic structure of catalytically active centers in covalent organic frameworks (COFs). Theoretical calculation reveals that adsorption ability of oxygen molecule (O2) can be finely tuned by the regulation of electronic structure and the binding strength of O2 is positively correlated with the electron donating ability of active center. As a result, the newly designed TP‐TD‐COF shows higher 2e− ORR activity and selectivity owing to the stronger electron donating ability and the higher adsorption strength of O2 on electron‐rich active center. This study reveals fundamental structure–activity relationship in H2O2 synthesis and offers a strategy for designing metal‐free COF catalysts through rational modulation of their electronic properties at molecular level.

Covalent Organic Frameworks for Photocatalytic Hydrogen Peroxide Generation

“…Thus, we emphasize that much more research should be devoted to both the design of COF-based photocatalysts and the engineering strategy of H 2 O 2 synthesis to achieve the goal. Surprisingly, only a few COFs have been identified as electrocatalysts for H 2 O 2 production. − However, the investigation of COF-based materials for photo­(electro)­catalytic H 2 O 2 production has not been explored yet, which may be an promising strategy in the near future. Thus, future research should focus on the exploration of more organic linkers that could facilitate the generation of H 2 O 2 from oxygen by photo­(electro)­catalysis via the oxygen reduction reaction pathway.…”

Recent advances in the role of MXene based hybrid architectures as electrocatalysts for water splitting

“…Density functional theory 71 calculations further revealed that the deliberate combination of COF-42 with Ti 3 C 2 T x provides a more diverse array of active positions with appropriate DG H values, resulting in an enhanced hydrogen generation rate. 85 In another study Wang et al prepared well connected 2D/2D hybrid by coupling of MXene with CoBDC nanosheets by a facile in situ grown approach. The as synthesized CoBDC/MXene catalyst showed lower over potential values of 29, 41 and 76 mV in alkaline, acidic and neutral environment respectively.…”

Covalent organic framework based photocatalysts for efficient visible-light driven hydrogen peroxide production

“…It should be noted that most of the COF-based photocatalysts reported thus far are based on imine linkages and recent studies have demonstrated that the construction of suitable linkages or linkage tailoring could also significantly affect the performance of the corresponding COFs. 59,60 As an example, the group of Thomas reported four chemically stable quinoline-4-carboxylic acid DMCR-COFs via the one-pot Doebner reaction for photocatalytic H 2 O 2 production, while the corresponding imine-based COF (imine-1) was also synthesized to compare its performance with those of DMCR-COFs (Fig. 11a).…”