Green synthesis of NiO nanoparticles and application in production of renewable H_2 from bioethanol

摘要

The present work proposes a green synthesis route for obtaining a nanoparticulate NiO catalyst suitable for the production of renewable H_2 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 H_2 yield was performed considering the effects of temperature (220-260 ℃), catalyst concentration (2-10 w/w), and reaction time (0.5-8 h), for reactions under autogenous pressure. The production of H_2 by the dehydro-genation of bioethanol resulted in the reduction of Ni~(2+) to face-centered cubic (fee) Ni~0. Transformation of the fcc phase to a hexagonal close-packed (hep) 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 H_2 (~99).