Transcript semiconductor nanosystem assembly for miniaturized fuel cell

LABORATORY OF NANOTECHNOLOGY
NATIONAL INSTITUTE FOR RESEARCH AND DEVELOPMENT IN MICROTECHNOLOGIES, IMT BUCHAREST, www.imt.ro
Metallic – semiconductor nanosystem assembly
for miniaturized fuel cell applications
Mihaela Miu*, Irina Kleps, Teodora Ignat, Monica Simion, Adina Bragaru
* [email protected]
Metallic nanoparticles present an enhanced electro-activity comparing with macroelectrodes due to their high surface-to-volume ratio
and their integration in complex devices allows improving of the sensor sensitivity or fuel cell efficiency, for example
→ A new metallic-
semiconductor nanosystem on Si has been studied for potential integration in a micro fuel cell as membrane electrode assembly (MEA) using specific processes
to nano- micro-electromechanical system (N/MEMS) technology
the Pt catalyst support
polished silicon wafer
nanosilicon
1
2
Silicon membrane has been subjected to an electrochemical process
spherical SiO2 nanoparticles offering similar huge area for
leading to porosification (nanostructuration) and consequently the
catalyst deposition, with similar size have been used as support
increase of the surface area and the density of chemically active sites
fabricated using a precipitation technique based on controlled
Si membrane morphology depends on process parameters,
and the pores diameter can be tuned from nm to µm
hydrolysis of a silicon alkoxide (tetraethylorthosilicate - TEOS)
From few nm to hundreeds of nm pores
in a mixture of ethanol containing aqueous ammonia.
70 – 100 nm
diameters
A Pt precursor solution (3.5mM H2PtCl6) was used for chemical impregnation
EDX spectrum for
nanoPt on big SiO2
nanoparticles (90 nm)
EDX spectrum for
nanoPt on PS
XRD analyses reveal the presence of (111) and
EDAX analyses reveal the improvement of Pt distribution
related to the diminish of SiO2 nanoparticle size
(200) crystallinity phases of Pt nanoparticles
In-plane diffraction
Spectru continuu-Mo
2000
300
Si(400)
1800
Pt(111)
1600
200
Pt(200)
1400
Pt crystallite phase distribution function
Lin (Counts)
I [Imp/10sec]
ALM35
100
1200
(a) 10 nm
(b) 30 nm
Si pores
Si pores
29.2 nm
0
1000
32
40
50
60
70
80
2-Theta - Scale
12
26.8 nm
EDX spectrum for
nanoPt on small SiO2
nanoparticles (18 nm)
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File:
(a) S1 PhaseID 300sm.raw - Step: 0.010 ° - Step time: 300. s
File:
(b) S4 PhaseID 300s_01_step0d05m.raw - Step: 0.050 ° - Step time: 300. s
00-001-1194 (D) - Platinum - Pt
90