Highly efficient CO2 photoreduction by ultralow-Ru-Loading ZIF-67

Developing highly efficient and low-cost photocatalysts for CO2 reduction is of critical importance for the conversion of CO2 to value-added chemicals. Here we report a Co-based zeolitic imidazole framework (ZIF-67) based photocatalyst with exceptional photocatalytic activity and durability for CO2 reduction. ZIF-67 is doped with dicyandiamide (DCD), the intermediate link with the trace Ru cocatalyst (0.0127 wt. %). The underlying reduction mechanism was unraveled by the joint experiment-theory study. The strong orbital coupling of ZIF-67-DCD-Ru series structure leads to strong CO2 adsorption, electron enrichment on cocatalyst, and minimum Gibbs free energy barrier of CO generation. The synthesized ZIF-67/DCD/Ru sample exhibits excellent CO2 photoreduction performance with a CO generation rate of 1495 mmol gRu−1 h−1 and achieves a record turnover frequency (TOF) of 151 h−1, representing top-level photocatalytic activity among all reported ZIFs-based photocatalysts. For the first time, our work points out a novel way to achieve high activity of ultralow noble metal loading photocatalyst and provides an in-depth understanding of the advances of the series structure.