Julio Cesar Vargas , Svetlana Ivanova , Sébastien Thomas , Anne-Cécile Roger and Véronique Pitchon
Article: Influence of Gold on Ce-Zr-Co Fluorite-Type Mixed Oxide Catalysts for Ethanol Steam Reforming
Catalysts 2012, 2(1), 121-138; doi:10.3390/catal2010121 - published online 3 February 2012
Show/Hide AbstractAbstract: The effect of gold presence on carbon monoxide oxidation and ethanol steam reforming catalytic behavior of two Ce-Zr-Co mixed oxides catalysts with a constant Co charge and different Ce/Zr ratios was investigated. The Ce-Zr-Co mixed oxides were obtained by the pseudo sol-gel like method, based on metallic propionates polymerization and thermal decomposition, whereas the gold-supported Ce-Zr-Co mixed oxides catalysts were prepared using the direct anionic exchange. The catalysts were characterized using XRD, TPR, and EDXS-TEM. The presence of Au in doped Ce-Zr-Co oxide catalyst decreases the temperature necessary to reduce the cobalt and the cerium loaded in the catalyst and favors a different reaction pathway, improving the acetaldehyde route by ethanol dehydrogenation, instead of the ethylene route by ethanol dehydration or methane re-adsorption, thus increasing the catalytic activity and selectivity into hydrogen.

Krisztián Csankó , Pál Sipos and István Pálinkó
Review: Monometallic Supported Gold Catalysts in Organic Transformations: Ring Making and Ring Breaking
Catalysts 2012, 2(1), 101-120; doi:10.3390/catal2010101 - published online 1 February 2012
Show/Hide AbstractAbstract: Supported gold catalysts are highly active in oxidation reactions. Beside the most frequently studied CO oxidation, they are readily applied in the epoxidation of more or less complex olefinic compounds using air or oxygen directly or other oxidants like peroxides of various kinds. Less frequently though, the reverse reaction, ring opening with single or double C–O scission is also investigated. These and other ring making and breaking reactions are reviewed, and the catalytic roles of gold species are described.

Endalkachew Sahle-Demessie , Venu Gopal Devulapelli and Ashraf Aly Hassan
Article: Hydrogenation of Anthracene in Supercritical Carbon Dioxide Solvent Using Ni Supported on Hβ-Zeolite Catalyst
Catalysts 2012, 2(1), 85-100; doi:10.3390/catal2010085 - published online 30 January 2012
Show/Hide AbstractAbstract: Catalytic hydrogenation of anthracene was studied over Ni supported on Hβ-zeolite catalyst under supercritical carbon dioxide (sc-CO₂) solvent. Hydrogenation of anthracene in sc-CO₂ yielded 100% conversion at 100 °C, which is attributed to the reduced mass transfer limitations, and increased solubility of H₂ and substrate in the reaction medium. The total pressure of 7 MPa was found to be optimum for high selectivity of octahydroanthracene (OHA). The conversion and selectivity for OHA increased with an increase in H₂ partial pressure, which is attributed to higher concentration of hydrogen atoms at higher H₂ pressures. The selectivity reduced the pressure below 7 MPa because of enhanced desorption of the tetrahydro-molecules and intermediates from Ni active sites, due to higher solubility of the surface species in sc-CO₂. The selectivity of OHA increased with the increase in catalyst weight and reaction time. The rate of hydrogenation of anthracene was compared with that found for napthalene and phenanthrene. The use of acetonitrile as co-solvent or expanded liquid with CO₂ decreased the catalytic activity.

Toni Riittonen , Esa Toukoniitty , Dipak Kumar Madnani , Anne-Riikka Leino , Krisztian Kordas , Maria Szabo , Andras Sapi , Kalle Arve , Johan Wärnå and Jyri-Pekka Mikkola
Article: One-Pot Liquid-Phase Catalytic Conversion of Ethanol to 1-Butanol over Aluminium Oxide—The Effect of the Active Metal on the Selectivity
Catalysts 2012, 2(1), 68-84; doi:10.3390/catal2010068 - published online 13 January 2012
Show/Hide AbstractAbstract: Direct catalytic valorization of bioethanol to 1-butanol over different alumina supported catalysts was studied. Thirteen (13) heterogeneous catalysts were screened in search for the optimal material composition for direct one-pot conversion of ethanol to 1-butanol. For the most promising catalyst, a 25% ethanol conversion with 80% selectivity (among liquid carbon products) to 1-butanol could be reached at 250 °C. Additionally, the reaction kinetics and mechanisms were further investigated upon use of the most suitable catalyst candidate.

Tsutomu Shiragami , Takayuki Tomo , Hikaru Tsumagari , Yasuyuki Ishii and Masahide Yasuda
Article: Hydrogen Evolution from Napiergrass by the Combination of Biological Treatment and a Pt-Loaded TiO₂-Photocatalytic Reaction
Catalysts 2012, 2(1), 56-67; doi:10.3390/catal2010056 - published online 22 December 2011
Show/Hide AbstractAbstract: Ethanol and pentose were produced from lignocellulosic napiergrass by the simultaneous saccharification and fermentation process (SSF) using hydrolytic enzyme and S. Cerevisiae. After the ethanol was removed, the pentose solution was subjected to photocatalytic hydrogen evolution with Pt-loaded TiO₂ under UV-irradiation. This process converted 100 g of napiergrass into 12.3 g of ethanol and 1.76 g of hydrogen whose total combustion energy of (∆H) was 615 kJ. This was close to the ∆H (639 kJ) of the pentose (13.6 g) and hexose (27.4 g) obtained by the cellulose-saccharification of 100 g of napiergrass.

Jan Mizera , Nika Spiridis , Robert P. Socha , Małgorzata Zimowska , Ryszard Grabowski , Katarzyna Samson and Józef Korecki
Article: The Influence of Base Metal (M) Oxidation State in Au-M-O/TiO₂ Systems on Their Catalytic Activity in Carbon Monoxide Oxidation
Catalysts 2012, 2(1), 38-55; doi:10.3390/catal2010038 - published online 22 December 2011
Show/Hide AbstractAbstract: Base metal promoted gold/titania catalysts were synthesized, characterized and tested in CO oxidation reaction. Catalysts containing dopant metals in higher oxidation states exhibited higher activity than catalysts containing dopants in reduced states. The activity of fresh catalysts promoted by Cu, Fe and Ni was similar to the unpromoted one, but treatment in reducing and oxidizing atmospheres revealed the supremacy of the copper promoted catalyst. The sequential deposition method proved to be better than the co-deposition—precipitation method. An attempt to explain these differences using XPS, FTIR and H₂ TPR was performed.