Materials Today Communications 10 (2017) 67–71
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Materials Today Communications
j ourna l ho me pa ge: www.elsevier.com/locate/mtcomm
Effect of the support on physicochemical properties and catalytic
performance of cobalt based nano-catalysts in Fischer-Tropsch
reaction
Sardar Ali
a,∗
, Noor Asmawati Mohd Zabidi
b
, Mohammed J. Al-Marri
a
,
Mahmoud M. Khader
a
a
Gas Processing Center, Qatar University, Doha, P. O. Box 2713, Qatar
b
Centralized Analytical Laboratory, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak, Malaysia
a r t i c l e i n f o
Article history:
Received 21 July 2016
Received in revised form
29 December 2016
Accepted 6 January 2017
Available online 17 January 2017
Keywords:
Cobalt
Support
Fischer-Tropsch reaction
a b s t r a c t
In this paper, comparative investigations of the effects of CNTs and -Al
2
O
3
on the physicochemical
properties and catalytic performances of Co based nano-catalyst during FTS have been presented. Cata-
lysts were prepared via a wet impregnation method and characterized by various analytical techniques
such as transmission electron microscopy (TEM), temperature programmed reduction (H
2
-TPR), carbon
dioxide temperature programmed desorption (CO
2
-TPD) and X-ray photoelectron spectroscopy (XPS).
Fischer-Tropsch reaction (FTS) was carried out in a fixed-bed microreactor (220
◦
C and 1 atm and with
H
2
/CO = 2 v/v, SV of 12 L/g h). Various characterization techniques revealed that Co nanocatalysts sup-
ported on CNTs and Al
2
O
3
were different in physicochemical properties. There was a stronger interaction
between Co and Al
2
O
3
support compared to that of CNTs support. CNTs support increased the reducibil-
ity, dispersion, active metal surface area and decreased Co particle size. A significant increase in% CO
conversion and FTS reaction rate was also observed over CNTs support compared to that of Co/Al
2
O
3
.
Co/CNTs resulted in higher C
5+
hydrocarbons selectivity compared to that of Co/Al
2
O
3
catalyst.
© 2017 Elsevier Ltd. All rights reserved.
1. Introduction
Due to limited resources of fossil fuel reservoirs, increase in
demand and environmental concerns, one of the possible ways to
meet the future energy challenges is the production of synthetic
fuel through Gas-to-Liquid (GTL) technology [1]. GTL deals with
the chemical conversion of synthesis gas into liquid fuels and other
valuable hydrocarbons products [2]. GTL can be based on several
feedstocks which have been expanded to include biomass, coal and
natural gas. Fischer-Tropsch Synthesis (FTS) is at the heart of the
Gas-to-Liquid technology which deals with the chemical conver-
sion of synthesis gas mixture into useful products consisting of a
variety of hydrocarbons [3]. Although all metals belonging to group
VIII have been found to exhibit considerable activity in this FTS but
due to high activity and selectivity cobalt based catalysts have been
used in commercials FTS [4].
It is generally accepted that the nature of the catalytic support
for FTS is one of the important parameters affecting its catalytic
∗
Corresponding author.
E-mail address: ali.sardar@qu.edu.qa (S. Ali).
performances. -Al
2
O
3
has been found to be one of the exten-
sively used supports for FTS catalysts [5]. Generally traditional
oxide supports serve catalytic purposes adequately, however there
are a number of drawbacks associated with these conventional
carriers such as stronger metal-support interaction, development
of hot spots on catalyst surface and phase transformation [6]. In
order to overcome these problems associated with the conven-
tional metal oxide supports, researchers have begun using carbon
as catalyst support. It is expected that this inert support would not
only reduce or eliminate reactivity with active phases of metals
but also maintain high stability at high temperatures and acidic or
basic environments [7–10]. A comparison of the catalytic activities
of -Al
2
O
3
and CNTs has been reported where it CNTs based Co cat-
alysts proved to be better in catalytic performances as compared to
-Al
2
O
3
supported Co catalyst [11]. However it is very important to
understand the chemistry of the physicochemical properties which
leads to this enhanced activity. In this paper, a comparative study of
the effects of CNTs and -Al
2
O
3
on the physicochemical properties
and catalytic performances of Co catalysts are presented.
http://dx.doi.org/10.1016/j.mtcomm.2017.01.004
2352-4928/© 2017 Elsevier Ltd. All rights reserved.