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Photocatalytic conversion of biomass is a potentially transformative concept in renewable energy. Dehydrogenation and hydrogenolysis of biomass-derived alcohols can produce renewable fuels such as H 2 and hydrocarbons, respectively. We have successfully used semiconductor-metal heterostructures for sunlightdriven dehydrogenation and hydrogenolysis of benzyl alcohol. The heterostructure composition dictates activity, product distribution, and turnovers. A few metal (M = Pt, Pd) islands on the semiconductor (SC) surface significantly enhance activity and selectivity and also greatly stabilize the SC against photoinduced etching and degradation. Under selected conditions, CdS-Pt favors dehydrogenation (H 2 ) over hydrogenolysis (toluene) 8:1, whereas CdS 0.4 Se 0.6 -Pd favors hydrogenolysis over dehydrogenation 3:1. Photochemically generated, surface-adsorbed hydrogen is useful in tandem catalysis, for example, via transfer hydrogenation. We expect this work will lead to new paradigms for sunlight-driven conversions of biomassrelevant substrates. KeywordsAlcohol dehydrogenation, Benzyl alcohol, CdS, photo-catalytic, photo-induced, product distributions, renewable energies, renewable fuels, semiconductor metals, tandem catalysis, transfer hydrogenations, biomass, cadmium compounds, hydrolysis ABSTRACT: Photocatalytic conversion of biomass is a potentially transformative concept in renewable energy. Dehydrogenation and hydrogenolysis of biomass-derived alcohols can produce renewable fuels such as H 2 and hydrocarbons, respectively. We have successfully used semiconductor-metal heterostructures for sunlight-driven dehydrogenation and hydrogenolysis of benzyl alcohol. The heterostructure composition dictates activity, product distribution, and turnovers. A few metal (M = Pt, Pd) islands on the semiconductor (SC) surface significantly enhance activity and selectivity and also greatly stabilize the SC against photoinduced etching and degradation. Under selected conditions, CdS-Pt favors dehydrogenation (H 2 ) over hydrogenolysis (toluene) 8:1, whereas CdS 0.4 Se 0.6 -Pd favors hydrogenolysis over dehydrogenation 3:1. Photochemically generated, surface-adsorbed hydrogen is useful in tandem catalysis, for example, via transfer hydrogenation. We expect this work will lead to new paradigms for sunlight-driven conversions of biomass-relevant substrates. SECTION: Energy Conversion and Storage; Energy and Charge Transport S olar-to-chemical energy conversion of biomass is a

Iron nanoparticles supported on mesoporous silica nanoparticles (Fe-MSN) catalyze the hydrotreatment of fatty acids with high selectivity for hydrodeoxygenation over decarbonylation and hydrocracking. The catalysis is likely to involve a reverse Mars-Van Krevelen mechanism, in which the surface of iron is partially oxidized by the carboxylic groups of the substrate during the reaction. The strength of the metal-oxygen bonds that are formed affects the residence time of the reactants facilitating the successive conversion of carboxyl first into carbonyl and then into alcohol intermediates, thus dictating the selectivity of the process. The selectivity is also affected by the pretreatment of Fe-MSN, the more reduced the catalyst the higher the yield of hydrodeoxygenation product. Fe-MSN catalyzes the conversion of crude microalgal oil into dieselrange hydrocarbons. Disciplines Materials Chemistry | Other Chemistry | Physical ChemistryComments NOTICE: this is the author's version of a work that was accepted for publication in Journal of Catalysis. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Catalysis, [314, (2014)