Fatty acids are important reaction intermediates in catalytic reduction of triglycerides. In this work, we conducted a detailed investigation of the adsorption and hydrodeoxygenation of butyric acid at Nb2O5(001) surface to understand the performance of Nb based catalytic support in biomass conversion by using density functional theory calculations. It has been found that the hydrodeoxygenation process starts with an adsorbed butyrate species in bidentate configuration at both clean and reduced surface with oxygen vacancy. The C-O bond activation facilitated by the interaction of the molecule and the surface Lewis acid can largely suppress the C-C bond cleavage, resulting in a dominant reductive deoxygenation pathway to generate butane. The unique surface structures of Nb2O5 are also found to play an important role in promoting the dissociative adsorption and further hydrogenation of the butyric acid through release of the surface tension. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.