Platinum Coated Copper Nanowires and Platinum Nanotubes as Oxygen Reduction Electrocatalysts

Platinum (Pt) coated copper (Cu) nanowires (Pt/CuNWs) are synthesized by the partial galvanic displacement of Cu nanowires (CuNWs) with a Pt loading of 18 wt %. Pt/CuNWs have an outer diameter of 100 nm, a length of 25–40 μm, and a theoretical Pt layer thickness of 2 nm. Cu templated Pt nanotubes (PtNTs (Cu)) with a wall thickness of 11 nm, an outer diameter of 100 nm, and a length of 5–20 μm are synthesized by the complete galvanic displacement of CuNWs. CuNWs are synthesized by the hydrazine reduction of Cu nitrate in sodium hydroxide. Oxygen reduction reaction (ORR) and durability experiments are conducted on Pt/CuNWs, PtNTs (Cu), silver templated PtNTs (Ag), and carbon supported Pt nanoparticles (Pt/C) to evaluate catalyst activity for use as proton exchange membrane fuel cell cathodes. The ORR area activities of Pt/CuNWs and PtNTs (Cu) are 1.501 and 1.506 mA cm_Pt^–2, respectively. Pt/CuNWs produce a dollar activity of 9.8 A $^–1 (dollar activity calculated from the DOE mass activity target for 2017–2020 of 0.44 A mg_PGM^–1). Durability testing of each catalyst shows improved retention of surface area and ORR activity in comparison to Pt/C

Mechanistic Study of Shape-Anisotropic Nanomaterials Synthesized via Spontaneous Galvanic Displacement

Among the broad portfolio of preparations for nanoscale materials, spontaneous galvanic displacement (SGD) is emerging as an important technology because it is capable of creating functional nanomaterials that cannot be obtained through other routes and may be used to thrift precious metals used in a broad range of applications including catalysis. With advances resulting from increased understanding of the SGD process, materials that significantly improve efficiency and potentially enable widespread adoption of next generation technologies can be synthesized. In this work, PtAg nanotubes synthesized via displacement of Ag nanowires by Pt were used as a model system to elucidate the fundamental mechanisms of SGD. Characterization by X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), and atom probe tomography (APT) indicates nanotubes are formed as Ag is oxidized first from the surface and then from the center of the nanowire, with Pt deposition forming a rough, heterogeneous surface on the PtAg nanotube

Mechanistic Study of Shape-Anisotropic Nanomaterials Synthesized via Spontaneous Galvanic Displacement

Among the broad portfolio of preparations for nanoscale materials, spontaneous galvanic displacement (SGD) is emerging as an important technology because it is capable of creating functional nanomaterials that cannot be obtained through other routes and may be used to thrift precious metals used in a broad range of applications including catalysis. With advances resulting from increased understanding of the SGD process, materials that significantly improve efficiency and potentially enable widespread adoption of next generation technologies can be synthesized. In this work, PtAg nanotubes synthesized via displacement of Ag nanowires by Pt were used as a model system to elucidate the fundamental mechanisms of SGD. Characterization by X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), and atom probe tomography (APT) indicates nanotubes are formed as Ag is oxidized first from the surface and then from the center of the nanowire, with Pt deposition forming a rough, heterogeneous surface on the PtAg nanotube

Mechanistic Study of Shape-Anisotropic Nanomaterials Synthesized via Spontaneous Galvanic Displacement

Among the broad portfolio of preparations for nanoscale materials, spontaneous galvanic displacement (SGD) is emerging as an important technology because it is capable of creating functional nanomaterials that cannot be obtained through other routes and may be used to thrift precious metals used in a broad range of applications including catalysis. With advances resulting from increased understanding of the SGD process, materials that significantly improve efficiency and potentially enable widespread adoption of next generation technologies can be synthesized. In this work, PtAg nanotubes synthesized via displacement of Ag nanowires by Pt were used as a model system to elucidate the fundamental mechanisms of SGD. Characterization by X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), and atom probe tomography (APT) indicates nanotubes are formed as Ag is oxidized first from the surface and then from the center of the nanowire, with Pt deposition forming a rough, heterogeneous surface on the PtAg nanotube