Surfactant-free synthesis of pdcu bimetallic foam and its catalytic reduction for 4-nitrophenol.

4‑Nitrophenol (4‑NP) pollution causes serious environmental risks. Traditional catalysts and surfactant‑modified metal foams suffer from insufficient active sites, poor stability and low catalytic efficiency, restricting their practical industrial applications. To solve these problems, this work develops a green, surfactant‑free one‑pot route to fabricate PdCu bimetallic foam catalysts with a unique 3D interwoven nanowire network, which effectively overcomes the above limitations. The catalyst is synthesized via room‑temperature reduction of Pd(NO3)2 and CuSO4 precursors by NaBH4, followed by water‑ethanol alternate washing and freeze‑drying. This fabrication method is simple, scalable and eco‑friendly without harsh synthetic conditions. Key structural and compositional advantages include: the 3D porous network reduces mass‑transfer resistance; surfactant‑free synthesis yields a clean catalyst surface to facilitate active site‑substrate interactions; ultrathin nanowires maximize exposed active sites; and Pd‑Cu electronic synergy decreases Pd consumption and optimizes electronic configuration for improved catalytic activity. Among as‑prepared catalysts, Pd3Cu1 exhibits the optimal performance, achieving complete 4‑NP reduction within 269 s with a high apparent rate constant (Kapp = 29.18 × 10‑3 s‑1) and TOF value of 2309 h‑1, as well as good reusability after five consecutive cycles. This green synthetic strategy and structural merits offer a facile pathway to design high‑performance bimetallic catalysts for environmental remediation.