Enhanced Solar CO2 Photoreduction to Formic Acid by Platinum Immobilization on Bipyridine Covalent Triazine Framework with Defects

The immobilization and structural analysis of platinum nanoparticles on a nitrogen‐rich, bipyridine‐containing covalent triazine framework (bpyCTF) having structural defects are disclosed by taking advantage of 15 N solid‐state nuclear magnetic resonance measurements at natural 15 N isotope abundance and X‐ray photoelectron spectroscopic analyses. The photocatalyst (Pt@bpyCTF) with structural defects reduces CO 2 to formic acid (FA) at a rate of 152 µmol h −1 g −1 and a selectivity higher than 95% over CO and H 2 in water under simulated solar light. The presence of amine defects and the immobilization of Pt cause improvement in the photocurrent density and CO 2 capture capacity (≈8% by weight) despite the moderate surface area (0.54 cm 3 g −1 )of the photocatalyst. Theoretical models and density functional theory calculations are employed to investigate the possible CO 2 reduction reaction (CO 2 RR) mechanisms. Considering the exceptional CO 2 capture capacity and high FA production using only CO 2 ‐bubbled water, this work highlights the great potential of nitrogen‐rich CTFs for photocatalyzed CO 2 RRs under green conditions.