Crystal Structure Control of Binary and Ternary Solid-Solution Alloy Nanoparticles with a Face-Centered Cubic or Hexagonal Close-Packed Phase

Abstract

The crystal structure significantly affects the physical and chemical properties of solids. However, the crystal structure-dependent properties of alloys are rarely studied because controlling the crystal structure of an alloy at the same composition is extremely difficult. Here, for the first time, we successfully demonstrate the synthesis of binary Ru–Pt (Ru/Pt = 7:3) and Ru–Ir (Ru/Ir = 7:3) and ternary Ru–Ir–Pt (Ru/Ir/Pt = 7:1.5:1.5) solid-solution alloy nanoparticles (NPs) with well-controlled hexagonal close-packed (hcp) and face-centered cubic (fcc) phases, through the chemical reduction method. The crystal structure control is realized by precisely tunning the reduction speeds of the metal precursors. The effect of the crystal structure on the catalytic performance of solid-solution alloy NPs is systematically investigated. Impressively, all the hcp alloy NPs show superior electrocatalytic activities for the hydrogen evolution reaction in alkaline solution compared with the fcc alloy NPs. In particular, hcp-RuIrPt exhibits extremely high intrinsic (mass) activity, which is 3.1 (3.2) and 6.7 (6.9) times enhanced compared to that of fcc-RuIrPt and commercial Pt/C.

Ordered PtCo Intermetallics Featuring Nitrogen‐Doped Carbon Prepared by Surface Coating Strategy for Oxygen Reduction Reaction

“…Figure 1c depicts the high‐resolution TEM (HRTEM) and the fast Fourier transformation (FFT). The clear lattice fringes spacing of 0.186 nm and 0.230 nm point to (110) and (111) planes of ordered fct‐PtCo alloy, respectively, which are consistent with the conclusion of XRD pattern [20] . As depicted in the high angle annular dark field scanning TEM (HAADF‐STEM) images and corresponding energy‐dispersive X‐ray spectroscopy (EDX) mapping (Figure 1d–h), the Pt, Co, C, and N elements are evenly scattered on the carbon support.…”

“…The clear lattice fringes spacing of 0.186 nm and 0.230 nm point to (110) and (111) planes of ordered fct-PtCo alloy, respectively, which are consistent with the conclusion of XRD pattern. [20] As depicted in the high angle annular dark field scanning TEM (HAADF-STEM) images and corresponding energy-dispersive X-ray spectroscopy (EDX) mapping (Figure 1d-h), the Pt, Co, C, and N Scheme 1. Schematic illustration of the main steps for the preparation of structurally ordered PtCo@NC-X catalysts.…”

Facile Manufacture of Oxide-Free Cu Particles Coated with Oleic Acid by Electrical Discharge Machining

“…Copper is used as a tool due to its excellent thermal and electrical conductivity, low cost, and wide availability. However, copper is highly oxidised in the normal environment compared with other conductive materials, and its crystalline structure is face-centred cubic [25]. Table 1 show experimental setup and operating and applied voltage.…”

Laser annealing-induced phase transformation behaviors of multicomponent metal alloy, oxide and nitride nanoparticle combinations

“…Inorganic compounds/mixtures of metal alloys and ceramics (e.g., oxide and nitride) form the bulk of widely-used materials in modern advanced technologies and broad applications such as electronics, clean energy generation and storage, healthcare, urban sustainability and nanomedicine [1][2][3] . Reducing metal and ceramic compounds to their nanoscale forms [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] , while increasing the number of principal elements with substantial concentrations [24][25][26][27][28] , enhance the overall diversity in terms of atomic interfaces, phase characteristics, compositions, as well as enable new emergent collective properties and performance [1][2][3] , e.g., high mechanical strength, ductility and toughness [29][30][31][32][33] , electrical, 17 magnetic 34,35 and electrochemical activities 28,[36][37][38][39] .…”

“…Although a plethora of top-down physical and/or bottom-up chemical synthesis approaches has been explored to grow inorganic metal and ceramic nanoparticles (NPs) with well-defined size, shape, composition, crystallinity and particle structure, majority of these studies focused on single-and binary-component inorganic NP structures and arrays [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] . More recent works have devoted particular attention in the crystal structure control of noble metal combinations to access new physiochemical properties via wet-chemical synthesis methods altering the metal precursors, reagents, and reaction conditions, and post-process steps that require several hours 10,13,14,16 . Further developments in the phase control of multicomponent nanomaterials are still desirable, however, as the expansion into nonprecious metal combinations and novel phases broaden the overall functionality and application space.…”