Cu-supported black phosphorus nanosheets for high-performance microwave-assisted catalytic bromobenzene coupling: a mechanistic study

Copper-based catalysts for Suzuki coupling reactions face limitations in efficiency and stability, while conventional palladium catalysts require high costs and harsh conditions. To address these challenges, we developed a bifunctional copper-loaded black phosphorus (Cu/BP) material. Initially, a series of Cu/BP catalysts (1–5 wt% Cu) were synthesized via wet chemical reduction. Subsequently, catalytic performance was evaluated using vector network analysis and a microwave catalysis system. Key results were obtained: Cu/BP-3 exhibited exceptional microwave absorption (minimum reflection loss: − 36.31 dB; effective bandwidth: 6.64 GHz). Under microwave heating (90 °C) with ultralow copper loading (0.25 mol%) in H 2 O/CH 3 OH (1:1 v/v), > 99.7% bromobenzene conversion was achieved within 2 h. This represents a 5.5-fold enhancement compared to conventional oil-bath heating. The catalyst maintained > 95% yields for bromobenzene substrates bearing strong electron-withdrawing/donating groups and ortho-substituents. Remarkably, > 95.4% activity retention was observed after 10 cycles, with copper leaching < 0.01 ppm. This work demonstrates that Cu/BP efficiently activates C–Br bonds through synergistic dielectric energy localization and interfacial charge transfer (P → Cu). It provides a new strategy for designing green, stable non-precious metal catalysts for microwave-driven reactions.