(398be) Combined Molecular Confinement and Metal-Support Interface Effects for Control of Hydrodeoxygenation Selectivity on Porous Pd@TiO2

Combined molecular
confinement and metal-support interface effects for control of
hydrodeoxygenation selectivity on porous Pd@TiO₂

Bingwen
Wang^a, Jing Zhang^b,
Will Medlin^b and Eranda
Nikolla^a

^aChemical Engineering Department, Wayne State University

5050 Anthony Wayne Drive,
Detroit, MI, 48202

^bChemical Engineering Department, University of Colorado

3415 Colorado Ave., UCB
596, Boulder, CO, 80303

Alcohols with aromatic substituents are key
intermediates formed from deconstruction of biomass^[1].
Selective deoxygenation of these alcohols is often desirable to produce fuels
or fuel additives. Two probe molecules that have received attention are benzyl
alcohol and furfuryl alcohol. Under hydrogenation conditions, various products
can be formed from these reactants. The hydrodeoxygenation (HDO) products,
toluene and 2-methyl furan, are the desired products for many fuels
applications. Efforts to design catalysts capable of selective HDO of such
oxygenated aromatic compounds have generally focused on two approaches:
combination of two materials with complementary activity for hydrogenation and deoxygenation^[2], and establishing
control over aromatic-surface interactions^[3].

In this study, we combine these approaches by
successful encapsulating Pd nanoparticles (NPs) within a porous TiO₂
film of controllable pore sizes to achieve high HDO selectivity, while
maintaining high catalytic activity (Figure 1)^[4].
Catalyst selectivity was found to be a strong function of both the presence of
Pd-TiO₂ interfacial sites and the pore size of the TiO₂
shell. Moreover, experiments measuring hydrogenation rates for olefins of
different molecular size strongly suggested that small pores hindered
adsorption of aromatics in a “flat-lying” configuration that has been
associated with non-selective C-C scission.

 SHAPE  \* MERGEFORMAT

Figure 1. (a) Scanning transmission electron
micrograph (b) bright field transmission electron micrograph and (c) pore size
distribution of synthesized Pd@TiO₂. (d) Selectivity and (e)
turnover frequency for HDO of furfuryl alcohol over different Pd catalysts.

REFERENCES

[1] A. M. Robinson,
J. E. Hensley, and J. W. Medlin, ACS Catal. 6 (2000) 5026.

[2] P. M. De
Souza, R. C. Rabelo-Neto, L. E. P. Borges, G. Jacobs,
B. H. Davis, T. Sooknoi, D. E. Resasco,
and F. B. Noronha, ACS Catal. 5 (2015) 1318.

[3] C. H. Lien,
and J. W. Medlin, J. Phys. Chem. C 118 (2014) 23783.

[4] J. Zhang, B.
Wang, E. Nikolla, and J. W. Medlin, Angew. Chem. Int. Ed. (2017), in press.