Synthesis of mesoscopic particles of multi-component rare earth permanent magnet compounds.

Multielement rare earth (R)-transition metal (T) intermetallics are arguably the next generation of high-performance permanent magnetic materials for future applications in energy-saving and renewable energy technologies. Pseudobinary Sm2Fe17N3 and (R,Zr)(Fe,Co,Ti)12 (R = Nd, Sm) compounds have the highest potential to meet current demands for rare-earth-element-lean permanent magnets (PMs) with ultra-large energy product and operating temperatures up to 200°C. However, the synthesis of these materials, especially in the mesoscopic scale for maximizing the maximum energy product ( B H m a x ), remains a great challenge. Nonequilibrium processes are apparently used to overcome the phase-stabilization challenge in preparing the R-T intermetallics but have limited control of the material's microstructure. More radical bottom-up nanoparticle approaches based on chemical synthesis have also been explored, owing to their potential to achieve the desired composition, structure, size, and shape. While a great achievement has been made for the Sm2Fe17N3, progress in the synthesis of (R,Zr)(Fe,Co,Ti)12 magnetic mesoscopic particles (MMPs) and R-T/T exchange-coupled nanocomposites (NCMs) with substantial coercivity ( H c ) and remanence ( M r ) , respectively, remains marginal.

Visible to near-infrared plasmon-enhanced catalytic activity of Pd hexagonal nanoplates for the Suzuki coupling reaction.

Photocatalytic conversion of solar energy to chemical energy is an efficient process in green chemistry because it facilitates room temperature chemical transformations by generating electronically excited states in photocatalysts. We report here on the robust synthesis, detailed structural characterization, and especially photocatalytic properties of plasmonic Pd hexagonal nanoplates for chemical reactions. The Pd hexagonal nanoplates are twin crystals, and composed of the top and bottom faces enclosed by the {111} planes with stacking faults and the side surfaces bound by mixed six {111} and six {100} planes. The Pd hexagonal nanoplates with well-defined and tunable longitudinal localized surface plasmon resonance (LSPR) have enabled the direct harvesting of visible to near-infrared light for catalytic cross coupling reactions. Upon plasmon excitation, the catalytic Suzuki coupling reactions of iodobenzene and phenylboronic acid accelerate by a plasmonic photocatalytic effect of plasmon induced hot electrons. The turnover frequency (TOF) of the Pd hexagonal nanoplates in a reaction illuminated with a λ = 300-1000 nm Xenon lamp at 176 mW cm(-2) was 2.5 and 2.7 times higher than that of non-plasmonic {111}-enclosed Pd nanooctahedra and {100}-enclosed Pd nanocubes, respectively, and 1.7 times higher than the TOF obtained when the reaction was thermally heated to the same temperature.