Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40th anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three-way catalysts (TWCs). Apart from this well-established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2-based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water-gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2-based materials has already been acquired, new characterization techniques and powerful theoretical methods are dee...

Fundamentals and Catalytic Applications of CeO2-Based Materials

This review surveys recent advances in the applications of layered double hydroxides (LDHs) in heterogeneous catalysis. By virtue of the flexible tunability and uniform distribution of metal cations in the brucite-like layers and the facile exchangeability of intercalated anions, LDHs-both as directly prepared or after thermal treatment and/or reduction-have found many applications as stable and recyclable heterogeneous catalysts or catalyst supports for a variety of reactions with high industrial and academic importance. A major challenge in this rapidly growing field is to simultaneously improve the activity, selectivity and stability of these LDH-based materials by developing ways of tailoring the electronic structure of the catalysts and supports. Therefore, this Review article is mainly focused on the most recent developments in smart design strategies for LDH materials and the potential catalytic applications of the resulting materials.

Catalytic applications of layered double hydroxides: recent advances and perspectives

Perovskites as substitutes of noble metals for heterogeneous catalysis: dream or reality.

With increased availability and decreased cost, ethanol is potentially a promising platform molecule for the production of a variety of value-added chemicals. In this review, we provide a detailed summary of recent advances in catalytic conversion of ethanol to a wide range of chemicals and fuels. We particularly focus on catalyst advances and fundamental understanding of reaction mechanisms involved in ethanol steam reforming (ESR) to produce hydrogen, ethanol conversion to hydrocarbons ranging from light olefins to longer chain alkenes/alkanes and aromatics, and ethanol conversion to other oxygenates including 1-butanol, acetaldehyde, acetone, diethyl ether, and ethyl acetate.

Recent Advances in Catalytic Conversion of Ethanol to Chemicals

This Review documents some examples of recent innovations in the field of catalytic selective oxidation from an industrial point of view. The use of alkanes as building blocks for the synthesis of bulk chemicals and intermediates is discussed, along with the main properties that catalysts should possess in order to efficiently catalyse the selective oxidation of these hydrocarbons. The currently developed processes for propene oxide and new processes under investigation for the synthesis of adipic acid are also described, highlighting innovative aspects for a better sustainability of the chemical industry.

Sustainability in Catalytic Oxidation: An Alternative Approach or a Structural Evolution?

Catalytic valorization of bioethanol over Cu-Mg-Al mixed oxide catalysts

Acido-basic and catalytic properties of transition-metal containing Mg–Al hydrotalcites and their corresponding mixed oxides

Ethanol conversion into butanol was performed over MMgAlO mixed oxide catalysts (M = Pd, Ag, Mn, Fe, Cu Sm, Yb). The highest butanol yields were obtained with the Pd-containing mixed oxide, which exhibited a remarkable stability during the reaction. A good correlation was found between the amount of basic sites of medium and high strength and the selectivity to butanol.

Catalytic Conversion of Ethanol into Butanol over M–Mg–Al Mixed Oxide Catalysts (M = Pd, Ag, Mn, Fe, Cu, Sm, Yb) Obtained from LDH Precursors

The methane total oxidation was studied over high surface area mesoporous Cu–Mg–Al mixed oxide catalysts obtained from layered double hydroxides (LDHs) precursors. XRD and H 2 -TPR revealed that both CuO and CuAl 2 O 4 phases were present in the calcined catalysts. The best results were obtained with the catalysts containing 10 and 20 at.% Cu, total conversion being achieved at temperatures lower than 525 °C in these cases. The catalyst containing 10% Cu showed the best specific activity per unit mass of copper. The influences of the contact time and of the methane concentration in the feed gas on the catalytic performances have also been investigated. The stability of the copper-based catalysts during the catalytic test was evidenced.

New Cu-based mixed oxides obtained from LDH precursors, catalysts for methane total oxidation

MMgAlO mixed oxide catalysts (M = Mn, Fe, Co, Ni, Cu, Zn, Ag and Pd) obtained from layered double hydroxide (LDH) precursors calcined at 1023 K were used in the complete oxidation of methane and the oxidative dehydrogenation of propane. The catalysts were characterized by XRD, N 2 adsorption, EDX and H 2 -TPR experiments. In the catalytic complete oxidation of methane, the Pd-based catalyst has been proved the most active, but the less stable catalyst. Other mixed oxides containing transition metals have been tested and their catalytic activity followed the order: MgAlO ≈ FeMgAlO  In the oxidative dehydrogenation of propane in the temperature range from 723 K to 873 K the propene selectivity passed through a maximum for the Mn- and Fe-containing catalysts and decreased continuously for the other transition metal-containing catalysts to the benefit of CO x for CuMgAlO and of cracking products for CoMgAlO, NiMgAlO and ZnMgAlO. Considering the propene yield, the catalysts can be ranked in the following order: CoMgAlO > MnMgAlO > NiMgAlO > ZnMgAlO > FeMgAlO > CuMgAlO. No straight correlation between the H 2 -TPR reducibility and the catalytic performances of the samples was found in the oxidative dehydrogenation of propane into propene. The effects of the contact time and of the propane-to-oxygen molar ratio on the catalytic performances of the most active CoMgAlO, MnMgAlO and NiMgAlO mixed oxides have been investigated.

Ioan-Cezar Marcu

Papers

Catalytic valorization of bioethanol over Cu-Mg-Al mixed oxide catalysts

Acido-basic and catalytic properties of transition-metal containing Mg–Al hydrotalcites and their corresponding mixed oxides

Catalytic Conversion of Ethanol into Butanol over M–Mg–Al Mixed Oxide Catalysts (M = Pd, Ag, Mn, Fe, Cu, Sm, Yb) Obtained from LDH Precursors

New Cu-based mixed oxides obtained from LDH precursors, catalysts for methane total oxidation

Transition metal-containing mixed oxides catalysts derived from LDH precursors for short-chain hydrocarbons oxidation