CO ₂ Cycloaddition Catalyzed by g‐C ₃ N ₄ @SiW ₁₁ Co

ABSTRACT The g‐C 3 N 4 @SiW 11 Co catalyst was synthesized through a three‐dimensional hollow g‐C 3 N 4 framework derived from cyanuric acid and melamine, followed by controlled deposition of SiW 11 Co. The resulting material exhibits a specific surface area of 135 m 2 g −1 higher than pristine g‐C 3 N 4 of 82 m 2 g −1 . Under thermocatalytic conditions (atmospheric pressure, 80°C), it achieves > 99% epoxide conversion within 8 h. When irradiated with a 12‐W white LED, the catalyst maintains > 99% conversion efficiency over 12 h under the same mild conditions. Notably, the catalyst shows excellent recyclability, retaining > 95% of its initial activity over seven consecutive cycles in both thermocatalytic and photocatalytic modes. Systematic mechanistic studies confirm that the enhanced performance stems from synergistic effects between the 3D hollow g‐C 3 N 4 support and SiW 11 Co, which collectively improve charge separation, CO 2 adsorption, and epoxide activation. This dual‐functional catalyst represents a significant advance over conventional single‐mode systems, offering a versatile platform for efficient CO 2 conversion under mild conditions.