(645g) In-Situ Drifts Studies over Cobalt Catalyst for Hydrogen Production from Ethanol

Ethanol dehydrogenation mechanism was investigated over cobalt catalyst
prepared by novel cellulose assisted combustion synthesis techniques [1-4].
Nanoparticles synthesis mechanism was studied using TGA/DTA analysis. The
effect of synthesis precursor ratio was also studied and correlated with
microstructural properties of the product. The amount of fuel content in the
combustion solution was found to greatly affect the phase and microstructure of
the synthesized catalysts. Along with the microstructure, changes in surface cobalt
oxidation states as a function of fuel ratio was also studied for various fuel
to oxidizer ratios using XPS. The cobalt catalyst was found to be highly active
for ethanol dehydrogenation reaction over a temperature of 50ºC– 400ºC. In situ
DRIFTS studies were conducted to understand the ethanol-metal interaction and
deduce a reaction pathway by monitoring the gas phase and surface adsorbed
species. The reaction mechanism was found to proceed via ethoxy formation and
subsequent generation of aldehyde species at 50ºC – 200ºC and formation of
carbon dioxide at 400ºC. Carbon formation was also observed as shown in the TEM
image (Fig. 1) of the spent catalyst, which supposedly comes from sequential
removal of H from adsorbed *CH₃ to produce hydrogen and carbon.

Figure 1: TEM image of spent Co catalyst after ethanol
dehydrogenation reaction

References

[1] A. S. Mukasyan, P. Dinka, Advanced
engineering materials 9 (2007) 653-657.

[2] A. Kumar, A.S. Mukasyan and E.E. Wolf,
Applied catalysis.A, General 372 (2010) 175-183.

[3] A. Kumar A.S. Mukasyan, E.E. Wolf,
Industrial engineering chemistry research 49 (2010) 11001-11008.

[4] A. Ashok, A. Kumar, R.R. Bhosale, M.A.H.
Saleh and Leo J.P. van den Broeke, RSC Advances 5 (2015) 28703-28712.