Nanoparticles alloying in liquids: Laser-ablation-generated Ag or Pd nanoparticles and laser irradiation-induced AgPd nanoparticle alloying

International audienceLaser irradiation of a mixture of single element micro/nanomaterials may lead to their alloying and fabrication of multielement structures. In addition to the laser induced alloying of particulates in the form of micro/nanopowders in ambient atmosphere which forms the basis of the field of additive manufacturing technology another interesting problem is the laser induced alloying of a mixture of single element nanoparticles in liquids since this process may lead to the direct fabrication of alloyed nanoparticles colloidal solutions. In this work Ag and Pd bare, surface ligand-free nanoparticles in solution were prepared by laser ablation of the corresponding bulk target materials separately in water, the two solutions were mixed and the mixed solution was laser irradiated for different time durations in order to investigate the laser induced nanoparticles alloying in liquid. Nanoparticles alloying and formation of AgPd alloyed nanoparticles takes place with the decrease of the intensity of the surface plasmon resonance peak of the Ag nanoparticles (at ~405 nm) with the irradiation time while the low wavelength interband absorption peaks of either Ag or Pd nanoparticles remain unaffected by the irradiation for times even as long as 30 mins. The alloyed nanoparticles have lattice constants with values between those of the pure metals which indicates that they consist of Ag and Pd in approximately 1:1 ratio similar to the atomic composition of the starting mixed nanoparticles solution. Formation of nanoparticle networks consisting of bimetallic alloyed nanoparticles and nanoparticles which remain as single elements even after the end of the irradiation, joining together, are also formed. The binding energies of the 3d core electrons of both Ag and Pd nanoparticles shift to lower energies with the irradiation time also a typical characteristic of AgPd alloyed nanoparticles

Modelisation autonome de l'environnement par un robot mobile

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : TD 81568 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Electrochemical Chlor-Iron Process for Iron Production from Iron Oxide and Seawater

The iron and steel industry accounts for ~ 8% of global greenhouse gas emissions. Electrochemical reduction of iron ore to metal for electric arc furnaces can enable sustainable steel production, but existing electrochemical processes require expensive capital or electrolytes. We report a low-temperature, electrochemical cell that consumes low-cost and abundant iron oxide and seawater, while co-producing NaOH and Cl2 with industrially relevant current densities reaching 300 mA cm-2 and current efficiencies >90 %. Freestanding films of phase-pure iron were formed after 4 h of continuous, stable electrolysis. The process can lead to levelized costs of iron that are competitive with iron produced in fossil-fuel-powered blast furnaces (< $500 per metric tonne) and the co-produced NaOH can be used for CO2 mineralization from the air or ocean, creating a net negative-emission process

Synthesis and characterization of nanocrystalline Mg2Ni prepared by mechanical alloying: Effects of substitution of Mn for Ni

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