TY - JOUR
T1 - In-situ generated Ni(OH)2 on chemically activated spent catalyst sustains urea electro-oxidation in extensive alkaline conditions
AU - Alex, Chandraraj
AU - Naduvil Kovilakath, Muhammed Safeer
AU - Rao, Nikhil N.
AU - Sathiskumar, Chinnusamy
AU - Tayal, Akhil
AU - Meesala, Lavanya
AU - Kumar, Pramod
AU - John, Neena S.
N1 - Publisher Copyright:
© 2024 Hydrogen Energy Publications LLC
PY - 2024/3/15
Y1 - 2024/3/15
N2 - Electrochemical urea oxidation reaction (UOR) is an efficient way to produce cost-effective hydrogen from urea-based wastes. We show that a chemical modification involving partial oxidation of the spent catalyst consisting of Ni@CNT, generated from industrial methane decomposition plants, is found to augment sustained UOR activity for a prolonged time in extensive alkaline conditions. The activated catalyst, Ni(OH)2–Ni@CNT exhibits a TOF of 0.5 s−1 and Tafel slope of 30 mV/dec retaining UOR activity for 60 h at ∼75 mA/cm2 in 1.6 M urea and 6 M KOH. In-situ X-ray absorption spectroscopy reveals that Ni in the activated spent catalyst possesses an average oxidation state of ∼1.4 and Ni(OH)2 content gets enhanced from 26 % to 30 % during UOR representing fresh Ni(OH)2 formation. The activated Ni nanoparticles wrapped with carbon nanotubes provide excellent activity, COx removal, turnover frequency, and favors in-situ formation of fresh Ni(OH)2 responsible for the activity retention.
AB - Electrochemical urea oxidation reaction (UOR) is an efficient way to produce cost-effective hydrogen from urea-based wastes. We show that a chemical modification involving partial oxidation of the spent catalyst consisting of Ni@CNT, generated from industrial methane decomposition plants, is found to augment sustained UOR activity for a prolonged time in extensive alkaline conditions. The activated catalyst, Ni(OH)2–Ni@CNT exhibits a TOF of 0.5 s−1 and Tafel slope of 30 mV/dec retaining UOR activity for 60 h at ∼75 mA/cm2 in 1.6 M urea and 6 M KOH. In-situ X-ray absorption spectroscopy reveals that Ni in the activated spent catalyst possesses an average oxidation state of ∼1.4 and Ni(OH)2 content gets enhanced from 26 % to 30 % during UOR representing fresh Ni(OH)2 formation. The activated Ni nanoparticles wrapped with carbon nanotubes provide excellent activity, COx removal, turnover frequency, and favors in-situ formation of fresh Ni(OH)2 responsible for the activity retention.
KW - Electrocatalytic urea oxidation
KW - Extensive alkaline condition
KW - Reuse
KW - Spent catalyst
KW - Urea waste remediation
KW - Urea-assisted hydrogen production
UR - http://www.scopus.com/inward/record.url?scp=85184759007&partnerID=8YFLogxK
U2 - 10.1016/j.ijhydene.2024.01.339
DO - 10.1016/j.ijhydene.2024.01.339
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AN - SCOPUS:85184759007
SN - 0360-3199
VL - 59
SP - 390
EP - 399
JO - International Journal of Hydrogen Energy
JF - International Journal of Hydrogen Energy
ER -
