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All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Synthesis and Characterization of Core-Shell Cu-Ru, Cu-Rh, and Cu-Ir Nanoparticles

Optimizing the use of expensive precious metals is critical to developing sustainable and low-cost processes for heterogeneous catalysis or electrochemistry. Here, we report a synthesis method that yields core-shell Cu-Ru, Cu-Rh, and Cu-Ir nanoparticles with the platinum-group metals segregated on the surface. The synthesis of Cu-Ru, Cu-Rh, and Cu-Ir particles allows maximization of the surface area of these metals and improves catalytic performance. Furthermore, the Cu core can be selectively etched to obtain nanoshells of the platinum-group metal components, leading to a further increase in the active surface area. Characterization of the samples was performed with X-ray absorption spectroscopy, X-ray powder diffraction, and ex situ and in situ transmission electron microscopy. CO oxidation was used as a reference reaction: the three core-shell particles and derivatives exhibited promising catalyst performance and stability after redox cycling. Furthermore, these results suggest that this synthesis approach may optimize the use of platinum-group metals in catalytic applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on Cu3Rh by Materials Project

Cu3Rh is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Rh is bonded to twelve Cu atoms to form RhCu12 cuboctahedra that share corners with four equivalent RhCu12 cuboctahedra, corners with eight equivalent CuCu8Rh4 cuboctahedra, edges with eight equivalent RhCu12 cuboctahedra, edges with sixteen equivalent CuCu8Rh4 cuboctahedra, faces with four equivalent RhCu12 cuboctahedra, and faces with fourteen CuCu8Rh4 cuboctahedra. There are eight shorter (2.60 Å) and four longer (2.63 Å) Rh–Cu bond lengths. There are two inequivalent Cu sites. In the first Cu site, Cu is bonded to four equivalent Rh and eight Cu atoms to form distorted CuCu8Rh4 cuboctahedra that share corners with twelve equivalent CuCu8Rh4 cuboctahedra, edges with eight equivalent RhCu12 cuboctahedra, edges with sixteen CuCu8Rh4 cuboctahedra, faces with four equivalent RhCu12 cuboctahedra, and faces with fourteen CuCu8Rh4 cuboctahedra. There are four shorter (2.60 Å) and four longer (2.63 Å) Cu–Cu bond lengths. In the second Cu site, Cu is bonded to four equivalent Rh and eight equivalent Cu atoms to form CuCu8Rh4 cuboctahedra that share corners with four equivalent CuCu8Rh4 cuboctahedra, corners with eight equivalent RhCu12 cuboctahedra, edges with twenty-four CuCu8Rh4 cuboctahedra, faces with six equivalent RhCu12 cuboctahedra, and faces with twelve CuCu8Rh4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CuRh by Materials Project

RhCu crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Rh sites. In the first Rh site, Rh is bonded to six equivalent Rh and six Cu atoms to form distorted RhCu6Rh6 cuboctahedra that share corners with twelve RhCu6Rh6 cuboctahedra, edges with twelve RhCu6Rh6 cuboctahedra, edges with twelve CuCu6Rh6 cuboctahedra, faces with six equivalent RhCu6Rh6 cuboctahedra, and faces with twelve CuCu6Rh6 cuboctahedra. All Rh–Rh bond lengths are 2.69 Å. All Rh–Cu bond lengths are 2.64 Å. In the second Rh site, Rh is bonded to ten equivalent Rh and six Cu atoms to form distorted RhCu6Rh10 cuboctahedra that share corners with ten CuCu6Rh6 cuboctahedra, corners with twelve RhCu6Rh6 cuboctahedra, edges with eight CuCu6Rh6 cuboctahedra, edges with sixteen RhCu6Rh6 cuboctahedra, faces with sixteen equivalent RhCu6Rh10 cuboctahedra, and faces with eighteen CuCu6Rh6 cuboctahedra. There are a spread of Rh–Rh bond distances ranging from 2.69–5.39 Å. All Rh–Cu bond lengths are 2.64 Å. There are three inequivalent Cu sites. In the first Cu site, Cu is bonded to six equivalent Rh and six equivalent Cu atoms to form distorted CuCu6Rh6 cuboctahedra that share corners with twelve CuCu6Rh6 cuboctahedra, edges with twelve equivalent RhCu6Rh6 cuboctahedra, edges with twelve CuCu6Rh6 cuboctahedra, faces with six equivalent CuCu6Rh6 cuboctahedra, and faces with twelve equivalent RhCu6Rh6 cuboctahedra. All Cu–Cu bond lengths are 2.69 Å. In the second Cu site, Cu is bonded to six Rh and six equivalent Cu atoms to form distorted CuCu6Rh6 cuboctahedra that share corners with five equivalent RhCu6Rh10 cuboctahedra, corners with twelve CuCu6Rh6 cuboctahedra, edges with ten RhCu6Rh6 cuboctahedra, edges with twelve CuCu6Rh6 cuboctahedra, faces with six equivalent CuCu6Rh6 cuboctahedra, and faces with fifteen RhCu6Rh6 cuboctahedra. All Cu–Rh bond lengths are 2.64 Å. All Cu–Cu bond lengths are 2.69 Å. In the third Cu site, Cu is bonded to six Rh and six equivalent Cu atoms to form distorted CuCu6Rh6 cuboctahedra that share corners with five equivalent RhCu6Rh10 cuboctahedra, corners with twelve CuCu6Rh6 cuboctahedra, edges with ten RhCu6Rh6 cuboctahedra, edges with twelve CuCu6Rh6 cuboctahedra, faces with six equivalent CuCu6Rh6 cuboctahedra, and faces with fifteen RhCu6Rh6 cuboctahedra. All Cu–Cu bond lengths are 2.69 Å.

36 MATERIALS SCIENCE↗