Nguyen Thi Bich Hien, Hyo Young Kim, Mina Jeon, Jin Hee Lee,1Muhammad Ridwan,Rizcky Tamarany, Chang Won Yoon*

Fuel Cell Research Center, Korea Institute of Science and Technology (KIST), Republic of Korea

Synthesis, Characterization and Catalytic Activity of Ru-N-C Hybrid Nanocomposite for Ammonia Dehydrogenation

IntroductionAmmonia (NH3) as a Chemical Hydrogen Storage Material

High hydrogen density (17.8wt%)High hydrogen density (17.8wt%)

Carbon-free chemical energyCarbon-free chemical energy

Developed technology for synthesis (Haber-Bosch process)Developed technology for synthesis (Haber-Bosch process)

Solid ammine complexesSolid ammine complexes

The capital and operating cost of the NH3 facility cheaper than H2 The capital and operating cost of the NH3 facility cheaper than H2 (20.2 M$ & 63.2 M$, respectively).(20.2 M$ & 63.2 M$, respectively).

Development of Efficient Development of Efficient CatalystsCatalysts

Ru-N-C Hybrid Nanocomposite (Ru-N-C)

Metal : Ru Metal : Ru – highly activity for ammonia – highly activity for ammonia decomposition decomposition

Support : black C sphere Support : black C sphere – cheap & high – cheap & high surface areassurface areas

Promoter : N Promoter : N – increase electron density of – increase electron density of metalmetal

Synthesis and Characterizations

High Catalytic Activities for ammonia dehydrogenation

Catalytic ActivitiesH2 Production via Ammonia dehydrogenation

Post-analysis of the spent catalyst

The reactant NH3 acted as a N-doping agent in Ru-C

Facile Pyrolysis Synthesis

ConclusionThe simple synthetic strategy presented herein provides an economical route for large-scale production of the highly active Ru-N-C catalyst.

The Ru-N-C catalyst displayed excellent performance for NH3 dehydrogenation with high stability.

The incorporated nitrogen atoms were proposed to play pivotal roles in:Generating uniformly distributed, small-sized Ru nanoparticles.Improving the thermal stability of the catalyst.Donating electron density to Ru via electronic interactions between Ru and N.

The as-developed Ru-N-C hybrid nanocomposite is thus applicable for on-site hydrogen production from ammonia with relevant catalyst optimization, and further provides insight for the development of various M-N-C catalysts (M = transition metals) for a number of chemical transformations.

Influence of Temperature Influence of GHSV & Temperature

AcknowledgementThis research was supported by Center of Excellence (CoE) program at Korea Institute of Science and Technology (KIST)

DehydrogenationDehydrogenation

N-doped Carbon as supports

Ru

CatalystBET Surface Areaa

(m2·g-1)

Pore Sizea

(nm)

Pore Volumea

(cm3·g-1)

Ru-N-C 898 4.7 1.05

Ru-C 1,110 5.4 1.57ICP

Ru-N-C 0.97 wt%

Ru-C 0.88 wt%

2NH3 3H2 + N2 H △ = 46kJ/mol

GHSV: 7,448 mLg-1h-1

500 oC

450 oC

400 oC

550 oC99.7%

81.5%

0 20 40 60 800

20

40

60

80

100

Ru-C

NH

3 co

nver

sion

(%)

Time (h)

Ru-N-C

Long-Term Stability

Nitrogen0.82wt%

TEM images of the prepared catalysts: (a, b) Ru-N-C and (c, d) Ru-C.

Hypothesis: The reactant NH3 acted as a N-doping agent in Ru-C

aDetermined by physical adsorption using N2