Highly sensitive hydrogen sensors based on SnO
2
nanomaterials with different morphologies
Yanbai Shen
a,*
, Wei Wang
a
, Anfeng Fan
a
, Dezhou Wei
a
, Wengang Liu
a
,
Cong Han
a
, Yansong Shen
b
, Dan Meng
c
, Xiaoguang San
c
a
College of Resources and Civil Engineering, Northeastern University, Shenyang 110819, China
b
Department of Chemical Engineering, Monash University, Clayton, VIC 3800, Australia
c
College of Chemical Engineering, Shenyang University of Chemical Technology, Shenyang 110142, China
article info
Article history:
Received 3 June 2015
Received in revised form
20 September 2015
Accepted 22 September 2015
Available online 23 October 2015
Keywords:
SnO
2
Nanomaterial
Morphology
Hydrogen
Gas sensor
abstract
SnO
2
nanomaterials with different morphologies, such as nanofilms, nanorods, and
nanowires, were fabricated by sputtering and thermal evaporation methods. Their
hydrogen sensing properties were then investigated. The structural characterizations
showed that the SnO
2
in these nanomaterials was tetragonal. The surface-to-volume ratio
of the nanofilms, nanorods, and nanowires increased, leading to an increase in the
effective surface area. Gas sensors based on these SnO
2
nanomaterials showed a reversible
response to hydrogen at various concentrations. The response order of the nanofilms,
nanorods and nanowires was enhanced while the peak operating temperature was
decreased from 250 to 150
C, and the response or recovery time became shorter. The re-
sults indicated that the sensor response effectively increased as the effective surface area
of the SnO
2
nanomaterials increased, demonstrating that gas-sensing properties could be
significantly improved by changing the nanomaterial morphology.
Copyright © 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights
reserved.
Introduction
Hydrogen (H
2
) has promise as a clean energy carrier that can
be generated from renewable energy sources, helping solve
some critical problems such as the depletion of fossil fuel
resources, pollution, and climate change due to greenhouse
gas emissions [1]. Currently, hydrogen is widely used in
ammonia synthesis, oil refining, fuel cells, and rocket engines
[2]. However, hydrogen production, storage, and transport can
be hazardous because hydrogen is flammable or explosive if
not handled properly [3]. Therefore, hydrogen sensors that are
capable of leak detection, especially at the ppm level, are
important.
To date, many studies have been conducted to develop
hydrogen sensors based on metal oxide semiconductors, such
as SnO
2
,WO
3
, ZnO, NiO, and Nb
2
O
5
, all of which were pre-
pared by various techniques, including sputtering, thermal
evaporation, chemical vapor deposition, hydrothermal syn-
thesis, and solegel [4e8]. Among these metal oxide semi-
conductors, SnO
2
, with a wide band gap of 3.6 eV at 300 K, has
proved to be a promising candidate for gas sensors [9,10],
photocatalysts [11,12], dye-sensitized solar cells [13,14], and
lithium-ion batteries [15,16]. Considerable efforts have been
* Corresponding author. Tel./fax: þ 86 24 83692711.
E-mail address: shenyanbai@mail.neu.edu.cn (Y. Shen).
Available online at www.sciencedirect.com
ScienceDirect
journal homepage: www.elsevier.com/locate/he
international journal of hydrogen energy 40 (2015) 15773e15779
http://dx.doi.org/10.1016/j.ijhydene.2015.09.077
0360-3199/Copyright © 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.