REU Final Presentation August 1 st, 2013 Analysis of the Promoter-Catalyst interaction between Mn and Rh by Transmission Electron Microscopy Ben Graham.

REU Final PresentationAugust 1st, 2013

Analysis of the Promoter-Catalyst interaction between Mn and Rh by Transmission Electron Microscopy

Ben GrahamDepartment of Materials Science and Engineering,

University of Alabama at Birmingham

Robert Klie, PhDDepartment of Physics, University of Illinois at Chicago

REU Final PresentationAugust 1st, 2013

Introduction• An alternative source of energy is a major concern for society.

• Draw Backs for traditional fermentation routes include:• Slow conversion process• Inefficient conversion process• By-products (such as ammonia)

• the Fischer-Tropsch mechanism can convert syngas(or bio-gas) to higher octane fuels such as ethanol.

• It is possible to increase the activity and selectivity of the mechanism by adding a catalyst and promoter. • Catalyst of interest is Rhodium promoted by Manganese

REU Final PresentationAugust 1st, 2013

IntroductionSEA strategy for increased promoter-metal interactions catalysts EELS mapping of SEA promoted catalyst

• Electron Energy Loss Spectroscopy (EELS) collects the inelastically-scattered electrons to determine chemical bonding.• J.R. Regalbuto, Catalyst Preparation: Science and Engineering, Taylor

& Francis/CRC Press, Boca Raton, 2006, pp. 297.

Sample was prepared in previous study

REU Final PresentationAugust 1st, 2013

2 4 6 8 10 12 14 160

5

10

15

20

25

30

35

40

Ethanol

1Mn3RhCNTs

2Mn3RhCNTs

CO Conversion %

Sel

ecti

vity

%

Introduction

• J. Liu and et al, Selective Absorption of Manganese onto Rhodium for optimized Mn/Rh/SiO2 Alcohol Synthesis Catalysts. print. 2013.

REU Final PresentationAugust 1st, 2013

TEM

• JEM 3010, basic TEM was used

• Transmitted elastically scattered electrons can be assembled into bright field images (composed of phase and mass contrast)

• D.B. Williams, C.B. Carter, Transmission Electron Microscopy. 1996, New York, Springer Science,7-141.

REU Final PresentationAugust 1st, 2013

TEM

• D.B. Williams, C.B. Carter, Transmission Electron Microscopy. 1996, New York, Springer Science,7-141.

REU Final PresentationAugust 1st, 2013

TEM Images3% Rh/CNT sample at 600Kx, atomic

resolution of particles3% Rh/CNT sample at 300Kx, ideal for

particle sampling

REU Final PresentationAugust 1st, 2013

TEM Images2% Mn/3%Rh/CNT sample at 600Kx, atomic

resolution of particles2% Mn/3%Rh/CNT sample at 300Kx, ideal for

particle sampling

• 1.96 nm total• 9 fringes • 0.22 nm each• (111) orientation

Emaps.mrl.uiuc.edu

REU Final PresentationAugust 1st, 2013

Particle Size Measurements• Average particle size for 3%Rh/CNT:

1.9 ± 0.6 nm

• Average Particle Size for 1%Mn/3%Rh/CNT

2.1 ± 0.5nm

3% Rh/CNT

1%Mn/3%Rh/CNT

Average Particle Size (nm)

Average Particle Size (nm)

Co

un

t

Co

un

t

REU Final PresentationAugust 1st, 2013

Particle Size Measurements• Average particle size for 2%

Mn/3%Rh/CNT:3.2 ± 0.6 nm

• Distribution for all samples were Gaussian or normal.

Catalyst Average Particle Size (nm)

Standard Deviation (±nm)

3% Rh/CNT 1.9 0.6

1% Mn/3% Rh/CNT

2.1 0.5

2% Mn/3% Rh/CNT

3.2 0.6

2%Mn/3%Rh/CNT

Average Particle Size (nm)

Co

un

t

REU Final PresentationAugust 1st, 2013

Particle Orientation

• 3.57nm• 16 Fringes• 0.223 nm each• In (111) plane

Catalyst Coordination Number(EXAFS)*

Bond Distance (Å)(EXAFS)*

Experimental

Lattice Parameter (Å)

(TEM)

3% Rh/CNT 4.9 2.67 4.1±0.1

1% Mn/3% Rh/CNT

5 2.67 4.2±0.1

2% Mn/3% Rh/CNT

4.8 2.67 3.8±0.1

• a= Lattice parameter

• d= measured d-spacing

• (hkl)= corresponding miller indices

• J. Liu and et al, Selective Absorption of Manganese onto Rhodium for optimized Mn/Rh/SiO2 Alcohol Synthesis Catalysts. print. 2013.

2%Mn/3%Rh/CNT image at 600k

REU Final PresentationAugust 1st, 2013

Discussion

Catalyst STEM* size (nm)

3%Rh/CNT 1.3 ±0.4

1%Mn/3%Rh/CNT 1.1±0.4

2%Mn/3%Rh/CNT 1.2 ±0.4

• STEM Dark Field Image of 2%Mn/3%Rh/CNTs (left)

• STEM Dark field image composed of Z-contrast

• TEM bright field image composed of phase and mass contrast

TEMCatalyst

Average Particle Size (nm)

Standard Deviation (±nm)

3% Rh/CNT 1.9 0.6

1% Mn/3% Rh/CNT

2.1 0.5

2% Mn/3% Rh/CNT

3.2 0.6

Rh

Mn

• J. Liu and et al, Selective Absorption of Manganese onto Rhodium for optimized Mn/Rh/SiO2 Alcohol Synthesis Catalysts. print. 2013.

REU Final PresentationAugust 1st, 2013

Conclusions & Future Work Determined nano-

particle size for promoted and un-promoted rhodium on carbon nano-tubes

Found evidence of manganese-rhodium interactions • Increase in particle size• Decrease in lattice

parameter

Examine Rh particles on a Mn substrate

Electron Diffraction analysis of samples

REU Final PresentationAugust 1st, 2013

Acknowledgments

NSF grant – EEC-NSF Grant #1062943 Nanoscale Physics Group Research Recourses Center East staff Dr. Takoudis, Dr. Jursich, and REU Staff

Thank You!Questions?