Single-Atom Palladium Nanoclusters: Unlocking Hydrogenation and Base-Free Aminocarbonylation Using an Economical CO Surrogate

Single-atom palladium nanoclusters (Pd-SA NCs) anchored on boron carbon nitride (BCN-Pd) were rationally constructed via an in situ thermal polymerization–impregnation strategy, yielding atomically dispersed Pd sites at an ultralow metal loading (0.39 wt %). Advanced structural characterization (EXAFS, XANES, and HRTEM) confirms the predominance of isolated Pd centers coordinated with C/N environments, along with highly dispersed Pd nanocluster features, establishing a catalytically versatile Pd–C–N interfacial structure. The BCN-Pd catalyst exhibits dual functionality, efficiently promoting both nitroarene hydrogenation and base-free aminocarbonylation reactions. Notably, oxalic acid dihydrate is employed as a safe, inexpensive, and environmentally benign CO surrogate, eliminating the need for hazardous gaseous CO. The catalyst delivers excellent activity and selectivity (>98% yield) under mild conditions, significantly reducing noble metal consumption while maintaining high catalytic efficiency. In addition to suppressing metal waste, the system demonstrates outstanding stability and recyclability, outperforming conventional Pd catalysts. Density functional theory (DFT) calculations elucidate the aminocarbonylation mechanism and reveal a strong correlation between theoretical predictions and experimental observations. Overall, this work establishes BCN-supported Pd single-atom architectures as an effective and sustainable catalytic platform for the synthesis of pharmaceutically relevant molecules.