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Improving the selectivity in the oxidative coupling of methane to ethane/ethylene poses a significant challenge for commercialization. The required improvements are hampered by the uncertainties associated with the reaction mechanism due to its complexity. Herein, we report about 90 % selectivity to the target products at 11 % methane conversion over Gd2O3‐based catalysts at 700 °C using N2O as the oxidant. Sophisticated kinetic studies have suggested the nature of adsorbed oxygen species and their binding strength as key parameters for undesired methane oxidation to carbon oxides. These descriptors can be controlled by a metal oxide promoter for Gd2O3. [ABSTRACT FROM AUTHOR]

Knowing the structure of catalytically active species/phases and providing methods for their purposeful generation are two prerequisites for the design of catalysts with desired performance. Herein, we introduce a simple method for precise preparation of supported/bulk catalysts. It utilizes the ability of metal oxides to dissolve and to simultaneously precipitate during their treatment in an aqueous ammonia solution. Applying this method for a conventional VOx−Al2O3 catalyst, the concentration of coordinatively unsaturated Al sites was tuned simply by changing the pH value of the solution. These sites affect the strength of V−O−Al bonds of isolated VOx species and thus the reducibility of the latter. This method is also applicable for controlling the reducibility of bulk catalysts as demonstrated for a CeO2−ZrO2−Al2O3 system. The application potential of the developed catalysts was confirmed in the oxidative dehydrogenation of ethylbenzene to styrene with CO2 and in the non‐oxidative propane dehydrogenation to propene. Our approach is extendable to the preparation of any metal oxide catalysts dissolvable in an ammonia solution. [ABSTRACT FROM AUTHOR]

Conversion of propane or butanes from natural/shale gas into propene or butenes, which are indispensable for the synthesis of commodity chemicals, is an important environmentally friendly alternative to oil-based cracking processes. Herein, we critically analyse recent developments in the non-oxidative, oxidative, and CO2-mediated dehydrogenation of propane and isobutane to the corresponding olefins over metal oxide catalysts. Particular attention is paid to (i) comparing the developed catalysts in terms of their application potential, (ii) structure–activity–selectivity relationships for tailored catalyst design, and (iii) reaction-engineering aspects for improving product selectivity and overall process efficiency. On this basis, possible directions for further research aimed at the development of inexpensive and environmentally friendly catalysts with industrially relevant performance were identified. In addition, we provide general information regarding catalyst preparation and characterization as well as some recommendations for carrying out non-oxidative and CO2-mediated dehydrogenation reactions to ensure unambiguous comparison of catalysts developed in different studies. [ABSTRACT FROM AUTHOR]

The article titled "Back Cover: Controlling Metal-Oxide Reducibility for Efficient C-H Bond Activation in Hydrocarbons" discusses the challenge of designing metal oxide catalysts and proposes a method to control their structural properties. The authors, Bingsen Zhang, Evgenii V. Kondratenko, Zhong-Wen Liu, and others, suggest that catalyst post-treatment in an NH3⋅H2O solution can dissolve and precipitate individual catalyst components, allowing for the tailoring of catalyst reducibility. This is important for C-H bond activation in hydrocarbons. The article provides valuable insights for researchers interested in catalyst design and C-H bond activation. [Extracted from the article]

In the article titled "Control of the Reducibility of Metal Oxides for Efficient Activation of C-H Bonds in Hydrocarbons," the authors discuss the challenge of designing metal oxide catalysts. They propose a method of controlling the structural properties of supported/bulk metal oxides through post-treatment in an NH3⋅H2O solution. This treatment allows for the dissolution and simultaneous precipitation of individual catalyst components, resulting in the ability to tailor catalyst reducibility. The authors highlight the importance of catalyst reducibility in the activation of C-H bonds in hydrocarbons. [Extracted from the article]

• ZrO 2 -based catalysts with Rh, Ru, Ir or Pt were tested for C 3 H 8 dehydrogenation. • The metals on LaZrO x and YZrO x positively affect the rate: Rh > Ru > Ir > Pt. • The metals facilitate formation of Zr cus sites and accelerate H 2 formation. • The metals affect propene adsorption and thus undesired side reactions. • C 3 H 6 selectivity over Rh- or Ru-containing catalysts increases with temperature. A series of catalysts on the basis of ZrO 2 , LaZrO x and YZrO x with supported Rh, Ru, Pt or Ir nanoparticles (NPs) were prepared. They were tested in the non-oxidative dehydrogenation of propane (PDH) to elucidate the effects of (i) the kind of supported metal and its loading, (ii) the size (1 nm or 5 nm) of NPs, (iii) metal oxide promoter for ZrO 2 and (iv) reaction temperature on PDH performance. Although the metals did not directly participate in propene formation, they improve catalyst activity through (i) promotion of Zr cus (cus means coordinatively unsaturated) formation and (ii) acceleration of hydrogen formation. The kind of metal was also established to be decisive for propene adsorption. The latter property has a negative effect on catalyst activity and propene selectivity. The most active Rh/YZrO x catalyst with 0.05 wt% Rh revealed about 1.6 times higher propene formation rate than a commercial-like K-CrO x /Al 2 O 3 or the state-of-the-art Ru/YZrO x. [ABSTRACT FROM AUTHOR]