Tunable Synthesis of Covalently Coupled G‐C ₃ N ₄ /RGO Nanohybrid and N‐Doped RGO via Scalable Precursor Composition Control for High Efficiency Metal Free Catalysis

Abstract The development of efficient, scalable metal‐free catalysts is vital for sustainable chemical processes. Here, we report a tunable one‐step thermal synthesis of 2D/2D graphitic carbon nitride/reduced graphene oxide (g‐C ₃ N ₄ /RGO) nanohybrids and nitrogen‐doped RGO (N‐RGO) by varying the urea‐to‐GO mass ratio. Urea‐rich mixtures yield RGO‐intercalated g‐C ₃ N ₄ , while GO‐rich compositions produce N‐RGO. GO promotes amine condensation and acts as a structural scaffold for g‐C ₃ N ₄ growth, while urea serves as a g‐C ₃ N ₄ precursor, nitrogen dopant, and reducing agent. XRD, FTIR, and XPS analyses confirm sheet exfoliation and the formation of interfacial CN covalent bonds, evidencing strong coupling between g‐C ₃ N ₄ and RGO. BET and electrochemical impedance results reveal that catalytic enhancement arises primarily from interfacial electronic coupling and accelerated charge transfer rather than surface area effects. The g‐C ₃ N ₄ /RGO‐60% composite exhibits optimal coupling and achieves 100% conversion of 4‐nitrophenol to 4‐aminophenol within 3 minutes ( k = 1.33 min ⁻¹ ), outperforming pristine RGO and g‐C ₃ N ₄ by 66‐ and 33‐fold, respectively. N‐RGO exhibits high efficiency ( k = 0.94 min ⁻¹ ), attributed to enhanced catalytic sites from nitrogen doping. This scalable, low‐cost method enables precise tuning of structureproperty relationships, offering high‐performance metal‐free catalysts for both dark and light‐driven environmental remediation and sustainable organic transformations.