Thermally induced intermetallic Rh1Zn1 nanoparticles with high phase-purity for highly selective hydrogenation of acetylene

Abstract

Ordered M₁Zn₁ intermetallic phases with structurally isolated atom sites offer unique electronic and geometric structures for catalytic applications, but lack reliable industrial synthesis methods that avoid forming a disordered alloy with ill-defined composition. We developed a facile strategy for preparing well-defined M₁Zn₁ intermetallic nanoparticle (i-NP) catalysts from physical mixtures of monometallic M/SiO₂ (M = Rh, Pd, Pt) and ZnO. The Rh₁Zn₁ i-NPs with structurally isolated Rh atom sites had a high intrinsic selectivity to ethylene (91%) with extremely low C₄ and oligomer formation, outperforming the reported intermetallic and alloy catalysts in acetylene semihydrogenation. Further studies revealed that the M₁Zn₁ phases were formed in situ in a reducing atmosphere at 400 °C by a Zn atom emitting–trapping–ordering (Zn-ETO) mechanism, which ensures the high phase-purity of i-NPs. This study provides a scalable and practical solution for further exploration of Zn-based intermetallic phases and a new strategy for designing Zn-containing catalysts.