One-step synthesis of carbon nanospheres with an encapsulated iron-nickel nanoalloy and its potential use as an electrocatalyst

A Versatile Route for Synthesis of Metal Nanoalloys by Discharges at the Interface of Two Immiscible Liquids

Discharge in liquid is a promising technique to produce nanomaterials by electrode erosion. Although its feasibility was demonstrated in many conditions, the production of nanoalloys by in-liquid discharges remains a challenge. Here, we show that spark discharge in liquid cyclohexane that is in contact with conductive solution, made of a combination of Ni-nitrate and/or Fe-nitrate and/or Co-nitrate, is suitable to produce nanoalloys (<10 nm) of Ni-Fe, Ni-Co, Co-Fe, and Ni-Co-Fe. The nanoparticles are synthesized by the reduction of metal ions during discharge, and they are individually embedded in C-matrix; this latter originates from the decomposition of cyclohexane. The results open novel ways to produce a wide spectrum of nanoalloys; they are needed for many applications, such as in catalysis, plasmonic, and energy conversion.

Synthesis and Hydrodynamic Modeling Study of Epoxy/Carbon Nanospheres (Epoxy-CNS) Composite Coatings for Water Filtration Applications

Coatings for filtration applications based on epoxy resin mixtures with isopropanol were synthesized using the dip-coating technique. The nanomaterials used were carbon nanospheres (CNS) synthesized by chemical vapor deposition (CVD) and commercially obtained Vulcan XC-72 (VC). The permeation flux and permeability of the coatings were determined by vacuum filtration of pure water applying different working pressures obtaining maximum values of 0.5555 cm3/s and 1.19 × 10−9 m2, respectively, for the CNS6 coating at 26,664 Pa. The minimum values obtained for the permeation flux and permeability were 0.0011 cm3/s and 1.21 × 10−11 m2, for the coating CNS3 at 39,996 Pa. This study analyzed the effect of nanomaterials and the addition of isopropanol at different volumes on the permeability of the coatings. The results show that the permeability was influenced by the number of pores present rather than by their diameter. The number of pores were obtained between the ranges 1–12 μm for all the coatings. The study of computational fluid dynamics (CFD) through a free and porous medium, showed that it is possible to accurately determine flow velocities (m/s) through and inside the composite coatings. Understanding the flow behavior is a practical strategy to predict the performance of new nanocomposite coatings.