Engineering earth-abundant copper(i) sensitizing centers in metal-organic frameworks for efficient photosynthesis

Rational construction of earth-abundant heterogeneous photocatalysts is of great importance for efficient and sustainable solar energy utilization. Herein, we have developed a series of earth-abundant MOF photocatalysts (Cu-1-MOF-Cu-5-MOF) by incorporating Cu(i) complexes with different steric functional groups, which represents an efficient strategy for regulating the sensitizing ability of MOFs by restricting the excited state configuration of Cu(i) sensitizing centers. Remarkably, Cu-5-MOF with strong steric functional groups can efficiently drive photocatalytic oxidative coupling of benzylamine with a yield of 90.2%, 11 times higher than that with Cu-1-MOF without steric functional groups (8.2%). Systematic investigations revealed that the introduction of strong steric functional groups (e.g. sec-butyl) into Cu based MOFs can enhance their visible-light absorption, photochemical stability and electron-hole separation efficiency, which contributed to facilitating the utilization of solar energy and interface electron/energy transfer for efficient photosynthesis. This work provides a new insight into rationally constructing earth-abundant and efficient MOF photocatalysts by engineering copper(i) sensitizing centers with steric functional groups at the molecular level.