Cu/Fe3O4 embedded polyethersulfone beads: a scalable and magnetically separable catalyst for hydrogen evolution from ammonia borane and selective hydrogenation of cinnamaldehyde

Abstract

In this work, we developed magnetically separable Cu@Fe₃O₄:PES based catalyst beads that enable both efficient hydrogen generation from ammonia borane (AB) and tandem reduction of organic compounds under mild and environmentally benign conditions. The structural and morphological properties of the Cu@Fe₃O₄ catalyst were thoroughly examined using XRD, SEM, EDX, TGA, TEM, Mössbauer, XPS and BET surface area analysis and the results confirm well-dispersed metallic Cu nanoparticles on the Fe₃O₄ support. The Cu@Fe₃O₄ catalyst demonstrated remarkable performance in AB hydrolysis, achieving a low activation energy of 21.7 kJ mol⁻¹, ensuring rapid hydrogen evolution at room temperature. To improve catalyst applicability, recovery, and reusability, polyethersulfone (PES) beads embedded with Cu@Fe₃O₄ nanoparticles were fabricated. The developed magnetically separable composite beads exhibited excellent structural integrity and catalytic performance for AB hydrolysis with 24.8 kJ mol⁻¹ activation energy. Simultaneously, Cu@Fe₃O₄:PES beads enabled efficient tandem reduction of various organic substrates, addressing a long-standing challenge in organic synthesis, the selective hydrogenation of α,β-unsaturated carbonyl compounds. Among these, the selective reduction of cinnamaldehyde to cinnamyl alcohol stands out as a benchmark organic transformation, typically hindered by competing CC hydrogenation. Remarkably, the Cu@Fe₃O₄:PES bead catalyst, in presence of AB, achieved this transformation in a one pot reaction within minutes, delivering >99% yield of highly pure single product. Overall, this study introduces a practical, scalable, and sustainable catalytic system that integrates green hydrogen production with value-added chemical synthesis, holding strong potential for industrial and energy applications.