• • Ni-TACOF-AB achieves a CO evolution rate of 11.71 mmol g−1 h−1 with 99.9% selectivity, 7.6 times higher than metal-free TACOF-AA, demonstrating the critical role of Ni coordination in enhancing photocatalytic CO2 reduction efficiency.
• • The synthesis leverages diketimine linkage formation via acenaphthenequinone and TAPPy, enabling the creation of MCOFs with controlled interlayer stacking (AA vs. AB) by simply adding NiCl2·6H2O, offering a facile route to tune COF properties.
• • DFT calculations confirm that Ni atoms lower the activation energy barrier of the rate-determining step in CO2RR, providing mechanistic insight into the enhanced activity and selectivity.
• • The AB stacking mode in Ni-TACOF-AB, induced by Ni coordination, is crucial for optimizing charge separation and electron transfer, as evidenced by the 7.6-fold improvement in CO production rate compared to the AA-stacked counterpart.