Zhao, ZhunHeck, Kimberly N.Limpornpipat, PongsakQian, HuifengMiller, Jeffrey T.Wong, Michael S.2019-08-282019-08-282019Zhao, Zhun, Heck, Kimberly N., Limpornpipat, Pongsak, et al.. "Hydrogen-generating behavior of Pd-decorated gold nanoparticles via formic acid decomposition." <i>Catalysis Today,</i> 330, (2019) Elsevier: 24-31. https://doi.org/10.1016/j.cattod.2018.06.044.https://hdl.handle.net/1911/107364Formic acid is a promising hydrogen storage material where hydrogen is generated via metal-catalyzed decomposition. Bimetallic catalysts are active for this reaction, but the mechanism has not been fully proven. Palladium metal supported on gold nanoparticles (Pd-on-Au NPs) has structural properties that are advantageous for studying aqueous-phase catalytic reactions. In this work, a series of Pd-on-Au NPs of varying Pd loadings (calculated in terms of Pd surface coverage, sc%) were synthesized, immobilized onto carbon, and studied for formic acid decomposition at room temperature. Pd-on-Au NPs were catalytically active, with a reaction rate constant as high as 137 m L-H2/gPd/min (corresponding to an initial turnover frequency TOF of 123 h−1) at a Pd loading of 300 sc%. In contrast, Au NPs were inactive, and Pd NPs were slightly active (5 mL-H2/gPd/min and TOF of 38 h−1). The Pd metal of Pd-on-Au catalysts are partially oxidized, and is readily reduced without changing the metal-on-metal structure during reaction, according to in situ x-ray adsorption spectroscopy measurements. CO formation was inhibited at a Pd loading of 300 sc%, suggesting that three-dimensional Pd ensembles favored the desired dehydrogenation pathway while single-atom and small two-dimensional Pd ensembles are active for the undesired dehydration pathway.engThis is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier.Journal articleNanoparticlesPalladiumGoldBimetallicFormic acidHydrogenCatalysthttps://doi.org/10.1016/j.cattod.2018.06.044