Enhancement of hydrogen generation using nanoaluminum particles produced by a wire explosion process

Abstract

Nanoaluminum particles were generated by a wire explosion process (WEP) in helium, argon, and nitrogen ambiences, by depositing energy equal to the vaporization energy of the conductor material volume. The size and shape of the generated nanoaluminum particles were analyzed using a transmission electron microscope (TEM). X‐ray diffraction (XRD) analysis was carried out to characterize the phase in nanoaluminum (Al) particles. Particle size distribution of the produced nano‐Al particles follows log‐normal distribution and the nanoparticles produced in helium were of smaller size compared to those produced in argon or nitrogen ambience. Hydrogen gas was generated on reacting aluminum nanoparticles with aqueous NaOH solution. It was observed that most of the oxides formed on reaction of Al and aqueous NaOH solution were bayerite at room temperature and boehmite at higher temperature. The formation of bayerite and boehmite was characterized using XRD and TEM studies. The reactions were also carried out at higher temperature to understand the hydrogen generation rate. Molarity of NaOH has a high influence on the rate of hydrogen generation. The rate constant of the reaction was calculated adopting the first order rate law for predicting the amount of hydrogen generation. Nickel (Ni) nanoparticles synthesized by WEP and copper sulfate (CuSO4) were used as catalysts and added to the reaction mixture of Al and aqueous NaOH solution to control the hydrogen generation rate. It was observed that the reaction rate of Al with NaOH medium has increased with the addition of CuSO4 and Ni nanoparticles due to the microgalvanic effect, thereby enhancing the hydrogen generation rate. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.