Prefabricated covalent organic framework nanosheets with double vacancies: anchoring Cu for highly efficient photocatalytic H2 evolution

Herein, we report a designed binuclear Cu-salphen covalent organic framework (COF) that can be exfoliated into ultrathin nanosheets (denoted as Cu-salphen-HDCOF-NSs) for photoactive catalytic hydrogen evolution. Its conjugated porous architecture, coupled with high loading of isolated Cu active sites, can not only efficiently increase the access of photogenerated charge to the surface redox reaction centers, but can also prohibit the recombination of photoexcitons. As a result, Cu-salphen-HDCOF-NSs exhibit a remarkable hydrogen evolution rate of 36.99 mmol g(-1) h(-1) under visible-light irradiation, which is far higher than those of reported Pt-assisted COF photocatalytic systems. This finding provides new insight into the design of COF catalysts for efficient artificial photocatalysis.