Charge Separation and Transfer Activated by Covalent Bond in Uio-66-Nh2/Rgo Heterostructure for Co2 Photoreduction

Controlling charge dynamics in mixed photocatalytic materials by interface design is of great significance for achieving efficient photocatalytic reduction of CO 2 . Here, the design of covalent bond between UiO-66-NH 2 and RGO successfully realized the efficient reduction of CO 2 . The presence of covalent bonds makes the CO yield up to 10.99 μmol·g -1 (66-NH 2 /RGO-3), which is significantly higher than that of photocatalysts without covalent bonds (5.11 μmol·g -1 for 66/RGO-3). XPS and FTIR characterization proved that there is a covalent bond between UiO-66-NH 2 and partially reduced graphene oxide. On the one hand, the UV-vis results show that 66-NH 2 /RGO-3 is beneficial to generate more photogenerated electrons compared with 66/RGO-3. On the other hand, the covalent bond strengthens the space charge separation state through the action of the internal electric field and the potential difference, and the photogenerated electrons can be quickly transferred to the RGO along the covalent bond. The combination of time-resolved PL decay curve and photoelectrochemical experiments clearly proves that covalent bonds can reduce the interface carrier transfer resistance and accelerate the charge transfer process. It is important that CO 2 -TPD and in-situ infrared indicate that the covalent bond has a stronger ability to adsorb and activate CO 2 , so that the photogenerated electrons quickly transferred to RGO can effectively participate in the reduction of CO 2 , thus speeding up the rate of CO 2 reduction to CO. Therefore, this work provides inspiration for improving charge dynamics through interface design to promote photoreduction of CO 2