Computational insight into the selectivity of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si14.svg" display="inline" id="d1e1333"><mml:mi>γ</mml:mi></mml:math>-valerolactone hydrodeoxygenation over Rh(111) and Ru(0001)

The observed difference in the selectivity towards alkane, ketone, and alcohol hydrodeoxygenation products over Ru and Rh catalysts is explored using a combination of density functional theory and microkinetics. Using γ -valerolactone as a model compound, we investigate the reaction mechanism in order to identify selectivity determining species. The effect of the coadsorbed water molecule as well as the higher adsorbate surface coverage on reaction barriers and energies is explored as well. The performed calculations suggest that the desired alkane product is formed from a ketone intermediate on Ru, and through both ketone and alcohol on Rh, although the selectivity towards alkane on Rh is much lower than on Ru. • Hydrodeoxygenation reaction of γ -valerolactone is explored on Ru(0001) and Rh(111) • The mechanism is studied computationally with DFT and microkinetic modeling • Two parallel alkane pathways with alcohol and ketone intermediates are identified • On Ru(0001) significant amounts of alkane are produced through the ketone pathway • Alcohols and ketones could be important intermediates for the reaction on Ru and Rh