Construction of Highly Active Coral‐Like Co/Ni‐BTC Catalyst and Its Application in CO2‐to‐CO Conversion

Abstract The photocatalytic reduction of CO2 using solar energy presents an effective strategy for CO2 mitigation and utilization. Metal–organic frameworks (MOFs), known for their exceptional CO2 adsorption capacities and unique structural features, are emerging as novel photoactive materials for CO2 reduction. In this study, rod‐like, reticular, and ball‐like Ni‐BTC were synthesized using Ni2⁺ ions and 1,3,5‐benzenetricarboxylic acid (H₃BTC). Among these, the rod‐like Ni‐BTC exhibited the narrowest optical band gaps and achieved an outstanding CO generation rate of 4.707 mmol/g/h. To further enhance the photocatalytic performance, Co2⁺ was partially substituted for Ni2⁺ in the rod‐like Ni‐BTC, resulting in the construction of bimetallic coral‐like Co/Ni‐BTC‐x (x = 1, 2, 3). The incorporation of Co2⁺ facilitated the transformation of the larger rod‐like Ni‐BTC particles into a coral‐like morphology with micro‐ and nanoscale dimensions. Compared to monometallic rod‐like Ni‐BTC, the bimetallic catalysts exhibited lower bandgap values, faster charge transfer rates, and superior photocatalytic CO₂ reduction activity. Notably, Co/Ni‐BTC‐2 achieved the highest CO generation rate of 7.392 mmol/g/h. This study demonstrates that the combination of morphological control and bimetallic approach is an effective strategy for enhancing the performance of MOF catalysts in the photochemical reduction of CO2.