A scalable in situ pyrolysis strategy was developed for the synthesis of Pd/BN nanocatalysts using melamine, boric acid, and palladium acetate as precursors. Strong electronic interactions between Pd nanoparticles and the BN support significantly enhanced catalytic performance, enabling highly efficient Suzuki coupling reactions. The Pd/BN catalyst achieved up to 99% yield across a broad substrate scope under ambient conditions in a 50% aqueous ethanol system. Additionally, it exhibited excellent stability and recyclability, maintaining high catalytic activity over at least ten cycles with minimal deactivation. Experimental studies and density functional theory (DFT) calculations confirmed that charge transfer at the Pd/BN interface lowered the energy barrier of the rate-determining step, accelerating reaction kinetics. The combination of mild conditions, high efficiency, and operational simplicity highlights the sustainability and scalability of this catalytic system, making it a strong candidate for industrial applications.