Catalytic properties of dispersed iron oxides
Fe
2
O
3
/MO
2
(M ¼ Zr, Ce, Ti and Si) for sulfuric acid
decomposition reaction: Role of support
Ashish Nadar
a,e
, Atindra Mohan Banerjee
a,*
, M.R. Pai
a,e
, R.V. Pai
b
,
Sher Singh Meena
c
, R. Tewari
d,e
, A.K. Tripathi
a,e
a
Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
b
Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
c
Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
d
Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400085, India
e
Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
article info
Article history:
Received 13 September 2017
Received in revised form
25 October 2017
Accepted 30 October 2017
Available online xxx
Keywords:
Supported iron oxide
Sulfuric acid decomposition
ε-Fe
2
O
3
Metal oxide-support interaction
Thermochemical cycle
Hydrogen generation
abstract
Supported iron oxides have been established as an important class of catalyst for high
temperature sulfuric acid decomposition. With an objective to elucidate the role of support
in modifying the overall catalytic properties of dispersed iron oxide catalysts, a series of
supported iron oxide based catalysts, Fe
2
O
3
(15 wt%)/MO
2
(M ¼ Zr, Ce, Ti and Si), synthe-
sized by adsorption-equilibrium method, is investigated for sulfuric acid decomposition
reaction. The structure of dispersed iron oxide phases largely depended on the nature of
the support oxide as revealed by the XRD and M€ ossbauer studies. a-Fe
2
O
3
is found to be
present as a major phase on ZrO
2
and CeO
2
support while ε-Fe
2
O
3
was the major phase on
silica supported iron oxide. On the other hand, presence of mixed oxide Fe
2
TiO
5
was
revealed over TiO
2
support. Strong dispersed metal oxide-support interactions inhibited
the total reduction of the dispersed phase on SiO
2
and TiO
2
as compared to complete
reduction of dispersed iron oxide on CeO
2
and ZrO
2
supports during temperature pro-
grammed reduction upto 1000
C. The order of catalytic activity at a temperature of ~750
C
is observed as Fe
2
O
3
/SiO
2
> Fe
2
TiO
5
/TiO
2
> Fe
2
O
3
/ZrO
2
> Fe
2
O
3
/CeO
2
, while at higher tem-
peratures of ~900
C the SO
2
yield is found to be comparable for all catalysts. A relationship
between the rate of sulfate decomposition and catalytic activity is established through
detailed TG-DTA investigations of sulfated catalyst and support. Considerable influence of
the support oxide on the composition, structure, redox properties, morphology and cata-
lytic activities of the active iron oxide dispersed phase has been observed. Thus, the sup-
port oxides operate as a critical component in the complex supported metal oxide catalysts
and these findings might influence the design and development of future high temperature
sulfuric acid decomposition catalysts.
© 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
* Corresponding author. Hydrogen Energy and Catalysis Section, Chemistry Division, Modular Labs, Bhabha Atomic Research Centre,
Mumbai 400085, India.
E-mail addresses: atinmb@barc.gov.in, atinmb@gmail.com (A.M. Banerjee).
Available online at www.sciencedirect.com
ScienceDirect
journal homepage: www.elsevier.com/locate/he
international journal of hydrogen energy xxx (2017) 1 e16
https://doi.org/10.1016/j.ijhydene.2017.10.163
0360-3199/© 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Nadar A, et al., Catalytic properties of dispersed iron oxides Fe
2
O
3
/MO
2
(M ¼ Zr, Ce, Ti and Si) for
sulfuric acid decomposition reaction: Role of support, International Journal of Hydrogen Energy (2017), https://doi.org/10.1016/
j.ijhydene.2017.10.163