Reaction-Induced Self-Assembly of CoO@Cu2 O Nanocomposites In Situ onto SiC-Foam for Gas-Phase Oxidation of Bioethanol to Acetaldehyde

Porous Silicon Carbide (SiC): A Chance for Improving Catalysts or Just Another Active-Phase Carrier?

There is an obvious gap between efforts dedicated to the control of chemicophysical and morphological properties of catalyst active phases and the attention paid to the search of new materials to be employed as functional carriers in the upgrading of heterogeneous catalysts. Economic constraints and common habits in preparing heterogeneous catalysts have narrowed the selection of active-phase carriers to a handful of materials: oxide-based ceramics (e.g. Al₂O₃, SiO₂, TiO₂, and aluminosilicates-zeolites) and carbon. However, these carriers occasionally face chemicophysical constraints that limit their application in catalysis. For instance, oxides are easily corroded by acids or bases, and carbon is not resistant to oxidation. Therefore, these carriers cannot be recycled. Moreover, the poor thermal conductivity of metal oxide carriers often translates into permanent alterations of the catalyst active sites (i.e. metal active-phase sintering) that compromise the catalyst performance and its lifetime on run. Therefore, the development of new carriers for the design and synthesis of advanced functional catalytic materials and processes is an urgent priority for the heterogeneous catalysis of the future. Silicon carbide (SiC) is a non-oxide semiconductor with unique chemicophysical properties that make it highly attractive in several branches of catalysis. Accordingly, the past decade has witnessed a large increase of reports dedicated to the design of SiC-based catalysts, also in light of a steadily growing portfolio of porous SiC materials covering a wide range of well-controlled pore structure and surface properties. This review article provides a comprehensive overview on the synthesis and use of macro/mesoporous SiC materials in catalysis, stressing their unique features for the design of efficient, cost-effective, and easy to scale-up heterogeneous catalysts, outlining their success where other and more classical oxide-based supports failed. All applications of SiC in catalysis will be reviewed from the perspective of a given chemical reaction, highlighting all improvements rising from the use of SiC in terms of activity, selectivity, and process sustainability. We feel that the experienced viewpoint of SiC-based catalyst producers and end users (these authors) and their critical presentation of a comprehensive overview on the applications of SiC in catalysis will help the readership to create its own opinion on the central role of SiC for the future of heterogeneous catalysis.

Ni-Foam-Structured Ni-Al2O3 Ensemble as an Efficient Catalyst for Gas-Phase Acetone Hydrogenation to Isopropanol

The free-standing Ni-Al₂O₃ ensemble derived from NiAl-layered double hydroxides (NiAl-LDHs) grown onto a Ni-foam has been developed for the exothermic gas-phase acetone hydrogenation to isopropanol. This approach works effectively and efficiently to achieve a unique combination of high activity/selectivity and enhanced heat/mass transfer stemmed from the Ni-foam. The outstanding catalyst is obtained by direct reduction of the un-calcined NiAl-LDH/Ni-foam, with a high turnover frequency of 0.90 s^-1, being capable of converting 90.8% acetone into isopropanol with almost 100% selectivity under stoichiometric H₂/acetone molar ratio, atmospheric pressure at 80 °C, and a WHSV_acetone of 10 h^-1. The catalyst derivation using the un-calcined NiAl-LDH/Ni-foam enables the Ni nanoparticles to be intertwined with Al₂O₃ to form a large Ni-Al₂O₃ interface, without interruption of impurities such as irreducible NiO (in the case of calcined NiAl-LDH/Ni-foam samples), which markedly improves the strong acetone adsorption next to the Ni⁰ hydrogenation sites, thereby leading to a dramatic improvement of catalyst activity.

Synergistic effect between gold nanoparticles and Fe-doped γ-MnO2 toward enhanced aerobic selective oxidation of ethanol

Gold nanoparticles supported on Fe-doped γ-MnO₂ were found to show a strong synergistic effect in the aerobic selective oxidation of ethanol to acetaldehyde.

Design and synthesis of a highly efficient heterogeneous MnCo2O4 oxide catalyst for alcohol oxidation: DFT insight into the synergistic effect between oxygen deficiencies and bimetal species

We report the design and synthesis of an oxygen vacancy-abundant spinel-structured MnCo₂O₄ oxide as a highly efficient catalyst for alcohol oxidation.

A review on fabricating heterostructures from layered double hydroxides for enhanced photocatalytic activities

LDH is a controllable 2D material for fabricating heterostructures with another semiconductor.

Cu3Pt1–Cu2O nanocomposites: synergistic effect-dependent high activity and stability for the gas-phase selective oxidation of alcohols

The catalyst Cu₃Pt₁–Cu₂O/SiC was facilely prepared via the in situ reaction of the corresponding compounds supported on SiC in the reaction stream.