Constructed electron transfer path and active sites with methyl and copper for efficient H2 evolution in covalent organic framework photocatalyst

Covalent Organic Frameworks (COFs), a new type of photocatalyst, have garnered widespread attention in photocatalytic water splitting for hydrogen evolution. However, the photogenerated electron-hole pairs in COFs are prone to recombination, which limits their performance. To address this issue, in this work, a donor-acceptor 1 -acceptor 2 (D-A 1 -A 2 ) type photocatalyst with dual acceptors is constructed, which loaded with Cu onto the electron acceptor sites of donor-acceptor (DA) COFs TpPa-2. Under visible light irradiation, the hydrogen evolution performance of this catalyst reaches 21.6 mmol/g/h. Using EXAS and XPS techniques, we have determined that Cu is bonded to the oxygen on the electron-accepting site of TpPa-2. In-situ XPS and EPR experiments further confirmed that Cu is an electron acceptor, effectively facilitated the transfer of photogenerated electrons, thereby significantly enhancing the photocatalytic performance. This work provides a strategy for the construction of highly efficient visible-light response COFs photocatalysts.