Zero-emission hydrogen production by CH4 pyrolysis over Ni/Ferrierite catalyst: Examination of the deactivated catalysts for electrical conductivity and H2 storage properties

Abstract

An economic route for the generation of hydrogen and utilization of carbon nanofibers (CNFs) was achieved by CH4 cracking over 20 wt%Ni/FER catalyst. The deactivated catalyst demonstrated electrical conductivity and hydrogen storage properties. TEM images displayed open mouths of CNFs and XRF data showed nearly 70% of nickel was recovered from the deactivated catalyst. Impedance studies of the CNFs exhibit prominence as battery electrodes due to their significant conductivity in the presence of nickel. While the hydrogen storage capacity was around 0.151 mmol (gcat)−1 of H2 on the obtained CNFs, it was increased to 0.361 mmol (gcat)−1 upon Ni recovery from the CNFs. A seven-fold increase in the H2 storage of ∼0.862 mmol (gcat)−1 was obtained upon Li doping, exhibiting its distinct property as a hydrogen storage material. The fresh, reduced, used, and deactivated catalysts were characterized by BET-SA, H2-TPR, XRD, Raman spectroscopy, TEM, and H2 pulse chemisorption and Ni/FER was established as an economically viable catalyst for high rates of H2 and CNF production.