Regulating the Topology of Covalent Organic Frameworks for Boosting Overall H 2 O 2 Photogeneration.

Photocatalytic oxygen reduction reactions and water oxidation reactions are extremely promising green approaches for massive H 2 O 2 production. Nonetheless, constructing effective photocatalysts for H 2 O 2 generation is critical and still challenging. Since the network topology has significant impacts on the electronic properties of two dimensional (2D) polymers, herein, for the first time, we regulated the H 2 O 2 photosynthetic activity of 2D covalent organic frameworks (COFs) by topology. Through designing the linking sites of the monomers, we synthesized a pair of novel COFs with similar chemical components on the backbones but distinct topologies. Without sacrificial agents, TBD-COF with cpt topology exhibited superior H 2 O 2 photoproduction performance (6085 and 5448 μmol g -1  h -1 in O 2 and air) than TBC-COF with hcb topology through the O 2 -O 2 ⋅ - -H 2 O 2 , O 2 -O 2 ⋅ - -O 2 1 -H 2 O 2 , and H 2 O-H 2 O 2 three paths. Further experimental and theoretical investigations confirmed that during the H 2 O 2 photosynthetic process, the charge carrier separation efficiency, O 2 ⋅ - generation and conversion, and the energy barrier of the rate determination steps in the three channels, related to the formation of *OOH, *O 2 1 , and *OH, can be well tuned by the topology of COFs. The current study enlightens the fabrication of high-performance photocatalysts for H 2 O 2 production by topological structure modulation.