High-Efficiency NO conversion via In-Situ grown covalent organic framework on g-C₃N₄ nanosheets with Single-Atom platinum photocatalyst

This study presents a chemically bonded Pt/TP-BPY-CN/g-C₃N₄ composite photocatalyst created through an in-situ growth method via Schiff base reaction between g-C₃N₄ and aldehyde-functionalized TP-BPY-COF. The −H-C-N-H- bonds formed at the g-C₃N₄ and TP-BPY-COF interface significantly boost electron communication, thereby substantially enhancing transfer efficiency between these two constituents. Besides, single-atom platinum incorporation via coordination establishes a Pt²⁺/Pt⁴⁺ redox cycle, aiding both oxidation and reduction of nitric oxide (NO). Consequently, the Pt/40TPBPY-CN composite achieves 65.3 % NO conversion, with almost 100 % oxidation selectivity towards NO₃^–. In-situ XPS analysis confirms the robust electron communication between TP-BPY-COF and g-C₃N₄ facilitated by −H-C-N-H- bonds, and the redox transformation between Pt²⁺ and Pt⁴⁺. In addition, DFT calculation provides a deeper insight into photocatalytic oxidation and reduction pathways, confirming an inhibition of N₂ desorption. This research underscores the benefits of chemically bonded heterostructures for improved electronic interactions and highlights the efficacy of bifunctional single-atom platinum in photocatalysis.