Structural and catalytic properties of supported Ni-Ir alloy catalysts for H2 generation via hydrous hydrazine decomposition

Lei He; Yanqiang Huang; Xiao Yan Liu; Lin Li; Aiqin Wang; Xiaodong Wang; Chung Yuan Mou; Tao Zhang

doi:10.1016/j.apcatb.2013.10.022

Structural and catalytic properties of supported Ni-Ir alloy catalysts for H₂ generation via hydrous hydrazine decomposition

Lei He, Yanqiang Huang, Xiao Yan Liu, Lin Li, Aiqin Wang, Xiaodong Wang, Chung Yuan Mou, Tao Zhang

Research output: Contribution to journal › Article › peer-review

123 Citations (Scopus)

Abstract

Iridium modified Ni/Al₂O₃ catalysts were prepared using Ni-Al hydrotalcite as precursor and tested in the selective decomposition of hydrous hydrazine for H₂ generation. Compared to Ni/Al₂O₃, NiIr_x/Al₂O₃ catalysts exhibited an increase of the reaction rate up to 6-fold and the H₂ selectivity from 93% to above 99%. The XRD and EXAFS analysis confirmed that Ir and Ni were present in the form of Ni-Ir alloy; and the H₂ differential heat of adsorption is appreciably lowered with increasing the amount of Ir in Ni-Ir alloy. High-temperature reduction, e.g. 700°C, induced the migration of Ir atoms into the Ni bulk and produced a Ni-skin surface. This structural modification is associated with a strongly decrease of activity and selectivity. EXAFS measurements were also performed on different noble metals (NM, Ir, Pt, and Au) modified Ni/Al₂O₃ catalysts in order to verify the extent of NM-Ni bimetallic bond formation, which was found to correlate with the catalytic performance.

Original language	English
Pages (from-to)	779-788
Number of pages	10
Journal	Applied Catalysis B: Environmental
Volume	147
DOIs	https://doi.org/10.1016/j.apcatb.2013.10.022
Publication status	Published - Apr 5 2014
Externally published	Yes

Keywords

EXAFS
Hydrazine
Hydrogen storage
Microcalorimeter
Nickel-iridium alloy

ASJC Scopus subject areas

Catalysis
General Environmental Science
Process Chemistry and Technology

Access to Document

10.1016/j.apcatb.2013.10.022

Cite this

@article{58c0eef841b342cebe2b5ed8bdacb90d,

title = "Structural and catalytic properties of supported Ni-Ir alloy catalysts for H2 generation via hydrous hydrazine decomposition",

abstract = "Iridium modified Ni/Al2O3 catalysts were prepared using Ni-Al hydrotalcite as precursor and tested in the selective decomposition of hydrous hydrazine for H2 generation. Compared to Ni/Al2O3, NiIrx/Al2O3 catalysts exhibited an increase of the reaction rate up to 6-fold and the H2 selectivity from 93% to above 99%. The XRD and EXAFS analysis confirmed that Ir and Ni were present in the form of Ni-Ir alloy; and the H2 differential heat of adsorption is appreciably lowered with increasing the amount of Ir in Ni-Ir alloy. High-temperature reduction, e.g. 700°C, induced the migration of Ir atoms into the Ni bulk and produced a Ni-skin surface. This structural modification is associated with a strongly decrease of activity and selectivity. EXAFS measurements were also performed on different noble metals (NM, Ir, Pt, and Au) modified Ni/Al2O3 catalysts in order to verify the extent of NM-Ni bimetallic bond formation, which was found to correlate with the catalytic performance.",

keywords = "EXAFS, Hydrazine, Hydrogen storage, Microcalorimeter, Nickel-iridium alloy",

author = "Lei He and Yanqiang Huang and Liu, {Xiao Yan} and Lin Li and Aiqin Wang and Xiaodong Wang and Mou, {Chung Yuan} and Tao Zhang",

note = "Funding Information: This work was supported by the National Natural Science Foundation of China ( 21103173 , 21173218 ) and the “Hundred Talents Program of Dalian Institute of Chemical Physics” . We also acknowledge the Shanghai Synchrotron Radiation Facility (SSRF) and the National Synchrotron Radiation Research Center of Taiwan (NSRRC) for the XAS experiment. ",

year = "2014",

month = apr,

day = "5",

doi = "10.1016/j.apcatb.2013.10.022",

language = "English",

volume = "147",

pages = "779--788",

journal = "Applied Catalysis B: Environmental",

issn = "0926-3373",

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TY - JOUR

T1 - Structural and catalytic properties of supported Ni-Ir alloy catalysts for H2 generation via hydrous hydrazine decomposition

AU - He, Lei

AU - Huang, Yanqiang

AU - Liu, Xiao Yan

AU - Li, Lin

AU - Wang, Aiqin

AU - Wang, Xiaodong

AU - Mou, Chung Yuan

AU - Zhang, Tao

N1 - Funding Information: This work was supported by the National Natural Science Foundation of China ( 21103173 , 21173218 ) and the “Hundred Talents Program of Dalian Institute of Chemical Physics” . We also acknowledge the Shanghai Synchrotron Radiation Facility (SSRF) and the National Synchrotron Radiation Research Center of Taiwan (NSRRC) for the XAS experiment.

PY - 2014/4/5

Y1 - 2014/4/5

N2 - Iridium modified Ni/Al2O3 catalysts were prepared using Ni-Al hydrotalcite as precursor and tested in the selective decomposition of hydrous hydrazine for H2 generation. Compared to Ni/Al2O3, NiIrx/Al2O3 catalysts exhibited an increase of the reaction rate up to 6-fold and the H2 selectivity from 93% to above 99%. The XRD and EXAFS analysis confirmed that Ir and Ni were present in the form of Ni-Ir alloy; and the H2 differential heat of adsorption is appreciably lowered with increasing the amount of Ir in Ni-Ir alloy. High-temperature reduction, e.g. 700°C, induced the migration of Ir atoms into the Ni bulk and produced a Ni-skin surface. This structural modification is associated with a strongly decrease of activity and selectivity. EXAFS measurements were also performed on different noble metals (NM, Ir, Pt, and Au) modified Ni/Al2O3 catalysts in order to verify the extent of NM-Ni bimetallic bond formation, which was found to correlate with the catalytic performance.

AB - Iridium modified Ni/Al2O3 catalysts were prepared using Ni-Al hydrotalcite as precursor and tested in the selective decomposition of hydrous hydrazine for H2 generation. Compared to Ni/Al2O3, NiIrx/Al2O3 catalysts exhibited an increase of the reaction rate up to 6-fold and the H2 selectivity from 93% to above 99%. The XRD and EXAFS analysis confirmed that Ir and Ni were present in the form of Ni-Ir alloy; and the H2 differential heat of adsorption is appreciably lowered with increasing the amount of Ir in Ni-Ir alloy. High-temperature reduction, e.g. 700°C, induced the migration of Ir atoms into the Ni bulk and produced a Ni-skin surface. This structural modification is associated with a strongly decrease of activity and selectivity. EXAFS measurements were also performed on different noble metals (NM, Ir, Pt, and Au) modified Ni/Al2O3 catalysts in order to verify the extent of NM-Ni bimetallic bond formation, which was found to correlate with the catalytic performance.

KW - EXAFS

KW - Hydrazine

KW - Hydrogen storage

KW - Microcalorimeter

KW - Nickel-iridium alloy

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