Atomic NbOx overlayers on palladium nanoparticles enhance selective hydrodehydroxylation

[Display omitted] •The NbOx atomic layers induced by SMSI effects were first observed, ca. 0.28 nm.•The catalyst with thin overlayers improved MF selectivity to 81.0% from 6.4%.•The resultant Pd/Nb2O5-500H presented both H2 activation and C – OH dissociation.•The layers over Pd NPs inhibited undesirable hydrogenation of formyl/furan ring.•CO poison experiments showed exclusive Pd1 sites are key to hydrodehydroxylation. The implementation of strong metal–support interactions (SMSI) is an effective design strategy that can be used to control reaction selectivity. In this study, we present evidence for the existence of SMSI between Nb2O5 and Pd, which results in the formation of an atomic thick layer of NbOx that coats the surface of Pd nanoparticles. The NbOx layer was found to profoundly affect the catalytic hydrodehydroxylation of 5-(hydroxymethyl)furfural (HMF) to 5-methylfurfural (MF). Under optimal reaction conditions, it significantly increased MF selectivity (from 6.4% to 81.0%) compared to an analogous control sample at iso-conversion. Through probing these two materials, the origin of this enhancement was attributed to the blocking of active sites responsible for the (undesirable) hydrogenation of C = O moieties. Importantly, however, the NbOx overlayer did not appear to influence the ability of the material to activate H2 and preferentially dissociate C – OH on Nb2O5, which are key steps in the hydrodehydroxylation mechanism.