Novel Nano-Rods PtSn electro-catalysts for fuel cells

Alex SchechterAriel University Center

July 2011

Fuel cells & electrochemistry Group Activities at AUC

• Non- Pt selective catalysts for DMFC and PEMFC , with high selectivity towards oxygen reduction in high concentrations of methanol

• Active and durable catalysts and catalyst support materials based on Sn and PtSn

• Novel design of fuel cell prototypes

• Hydrogen generation materials and devices from primary hydrides for PEMFC

Direct methaol fuel cell(DMFC) Concept

Membrane/ Separator/ Electrolyte

6e- 6e-

In Air – O2

Water + Methanol Residue

3H2O

CO2 Out

Methanol solution In

6H+

Anode Cathode

Challenges in Fuel cell catalysis

Activity

Price & Availability

Durability over time

Pt instability in fuel cells

P. J. Ferreira, and Y. Shao-Horn. Electrochem. Solid State Lett. 10, B60 (2007).

Metallic Sn core

SnO2 shell

Tin (Sn) Nanorods in Core shell as catalyst material for fuel cell

Impregnation with NaBH4 as a reduction agent Electrodeposition method

Microwave irradiation

Ultrasound irradiation Atomic layer deposition

Sn NR

Catalyst on Sn NR

Sn/SnO2 nano roads prepared at AUC fuel cells lab

Tin Melting in a Core-shell NR structure

Sn m.p.

Pt

PtSn

-3.50E-01

-3.00E-01

-2.50E-01

-2.00E-01

-1.50E-01

-1.00E-01

-5.00E-02

0.00E+00

5.00E-02

1.00E-01

1.50E-01

-0.2 0 0.2 0.4 0.6 0.8 1

Voltage, V

Cu

rren

t, m

A

1st cycle

50th cycle

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 50 100 150 200 250 300 350 400 450

E, m

V

I, mA/mg Pt in anode

Commercial PtRu

Microwave synthesized PtSn

NR 50nm x 300nm provide very high surface area.

Stable support for Pt in acid environment.

Low resistivity due to a core shell structure.

Formation of conductive 3D network structure is made plausible by low T sintering of NR. Highly active PtSn alloy and Pt on SnO2 support show excellent activity towrdes most widely used fuels in fuel cells. Use of advance methods (Electrochemical ALD) and can increase the catalysts utilization and reduce the fuel cell cost.

Partnership Sought

Collaborator 1Fuel cell material developing group or company seeking

alternatives catalysts to the state of the art Pt or PtRu on carbon support

Collaborator 2• Dynamic fluidic calculation of 3D-NR structure• Mathematical model mass and electrical balance of the fuel

cell Collaborator 3• Theoretical quantum mechanical study of methanol&

hydrogen oxidation on Pt and PtSnO2

acknowledgements

• Dr. Hanan Teller• Dr. Olga Krachevsky

Thank You

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