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Fabrication of Ni‐Fe LDH/GF anode for enhanced Fe(III) regeneration in fuel cell‐assisted chelated‐iron dehydrosulfurization process
Author(s) -
Zhai LinFeng,
Mao HaiZhou,
Sun Min
Publication year - 2018
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.5323
Subject(s) - anode , catalysis , chelation , chemistry , cathode , ion exchange , faraday efficiency , inorganic chemistry , graphite , nuclear chemistry , materials science , electrode , ion , metallurgy , organic chemistry
BACKGROUND The incorporation of an air‐cathode fuel cell into the chelated iron dehydrosulfurization process realizes simultaneous recovery of electricity and elemental sulfur from H 2 S. However, the slow oxidation kinetics of chelated Fe(II) in the fuel cell limits the efficiency of such a process. RESULTS A novel Ni–Fe layered double hydroxides/graphite felt (Ni‐Fe LDH/GF) anode is fabricated to speed up the electro‐oxidation of chelated Fe(II). The prepared Ni‐Fe LDH gives a formula of Ni 0.68 Fe 0.32 (OH) 2 (CO 3 ) 0.16 ·yH 2 O and covers the GF as nano‐scaled hexagonal plate. The Ni‐Fe LDH demonstrates stable catalytic activity towards the electro‐oxidation of Fe(II)‐EDTA, evidenced by the enhanced reaction rate and decreased reaction resistance at LDH modified GF. As a result, the total time for Fe(II)‐EDTA oxidation in the fuel cell reduces significantly from 90 to 50 h when Ni‐Fe LDH/GF composite is used instead of GF, and the coulombic efficiency (CE) of circuit is increased by 53% concomitantly. The catalysis activity of Ni‐Fe LDH is proposed to be due to its anion‐exchange ability for Fe(EDTA) 2− and Fe(OH)(EDTA) 3− , which benefits the diffusion of the two dominant Fe(II) species onto the electrode surface to perform electro‐oxidation. CONCLUSION In summary, the fabricated Ni‐Fe LDH/GF anode material is suitable for enhancing the Fe(III) regeneration in an air‐cathode fuel cell, and can further improve the efficiency of the chelated‐iron dehydrosulfurization process. © 2017 Society of Chemical Industry