Advanced Functional Materials, Vol.26, No.31, 5658-5668, 2016
Ultrafine Alloy Nanoparticles Converted from 2D Intercalated Coordination Polymers for Catalytic Application
Supported multimetallic alloy nanoparticles (NPs) have shown great potential for applications owing to combined functions of constituent metals, and more remarkably, enhanced physicochemical properties and even novel synergistic effects that are not possessed by their parent metals. Nevertheless, synthesizing this kind of nanocomposites has been a long-standing challenge using conventional wet chemistry. Here, this study reports an efficient, versatile strategy for the preparation of multimetallic alloy NPs supported by layered double hydroxides (LDH) and/or layered double oxides (LDO). In this approach, different metal precursors are intercalated stepwise into the gallery space of LDH. Along with the coordination reaction between the metal precursors, 2D cyanide bridged coordination polymers (CP) are formed in the confined space. Afterward, supported multimetallic alloy NPs can be obtained via either liquid-phase reduction or thermal autoreduction. Due to the homogeneous mixing of metals in the 2D CP, ultrafine alloy NPs can be obtained with high particulate uniformity and compositional tailorability. A large series of supported binary alloy NPs (FePd, FePt, CoPd, CoPt, NiPd, NiPt, and PtPd) and ternary alloy NPs (FePdPt, FeNiPt, FeCoPt, and NiCoPt) are successfully synthesized with this approach. The resulting supported multimetallic alloy NPs present great potential in numerous applications. To demonstrate their workability, one class of LDH/NiPd nanocomposite is explored as a model heterogeneous catalyst with respect to the carbon-carbon cross-coupling reactions (Suzuki-Miyaura, Heck, and Sonogashira cross-coupling reactions).