Green synthesis of NiO nanoparticles and application in production of renewable H2 from bioethanol

Abstract

The present work proposes a green synthesis route for obtaining a nanoparticulate NiO catalyst suitable for the production of renewable H2 from bioethanol. The synthesis is based on the Pechini method, with few process steps, simplicity, and chitosan biopolymer as precursor. The catalyst was characterized using XRD, TEM, DLS, BET, and TGA techniques. Optimization of the process in terms of the H2 yield was performed considering the effects of temperature (220–260 °C), catalyst concentration (2–10% w/w), and reaction time (0.5–8 h), for reactions under autogenous pressure. The production of H2 by the dehydrogenation of bioethanol resulted in the reduction of Ni2+ to face-centered cubic (fcc) Ni0. Transformation of the fcc phase to a hexagonal close-packed (hcp) phase occurred during the reaction. From the third hour of reaction onwards, there were significant increases in the volume of the gas phase and the selectivity towards H2 (∼99%).