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The suitability of a commercial and industrially applied Cu‐based catalyst for the synthesis of methanol by CO2 hydrogenation was investigated. Unexpectedly, this system showed high stability and well‐performance under conditions that may be relevant for chemical energy conversion using hydrogen and energy from renewable technologies. This Cu‐based catalyst demonstrated excellent suitability for dynamical process operation that may be essential for effective compensation of the volatility of renewable energy sources. [ABSTRACT FROM AUTHOR]

Abstract: One of the major goals of current research on energy conversion is the mitigation of CO2 emission. A beneficial scenario for CO2 utilization is the catalytic conversion of industrial waste or process gases into valuable products. Within the cross‐industry approach of Carbon2Chem® the synthesis of methanol from steel mill exhaust gases is a promising way to close the carbon cycle based on additional sustainably produced H2. New catalyst requirements have to be met due to fluctuating feed gas composition and availability as well as gas separation and purification issues. [ABSTRACT FROM AUTHOR]

LaNiO3 perovskite is an interesting precursor for Ni/L2O3 catalysts for the dry reforming of methane at high temperatures. Precursors have been synthesized by co-precipitation without, with 2.5 at%, and with 5 at% Ru doping. The presence of Ru leads to a stabilization of the perovskite structure and hinders the decomposition into NiO and Ruddlesden-Popper mixed oxides Lan+1NinO3n+1, which was observed for the Ru-free sample upon calcination at 1000 °C (n = 3). Upon reduction in hydrogen, a mechanism involving at least two steps was observed and the first major step was identified as the partial reduction of the precursor leading to a LaNiO2.5-like intermediate. The second major step is the reduction to Ni metal supported on L2O3 independent of the Ru content of the catalyst. In the presence of Ru, indications for Ni-Ru alloy formation and for a higher dispersion of the metallic phase were found. The catalytic activity in DRM of the catalyst containing 2.5% Ru was superior to the catalysts with more or without Ru. Furthermore, the propensity of coke formation was reduced by the presence of Ru. [ABSTRACT FROM AUTHOR]

The catalytic performance of a Ni/MgAlOx catalyst was investigated in the high temperature CO2 reforming of CH4. The catalyst was developed using a Ni, Mg, Al hydrotalcite-like precursor obtained by co-precipitation. Despite the high Ni loading of 55 wt%, the synthesized Ni/MgAlOx catalyst possessed a thermally stable microstructure up to 900 °C with Ni nanoparticles of 9 nm. This stability is attributed to the embedding nature of the oxide matrix, and allows increasing the reaction temperature without losing active Ni surface area. To evaluate the effect of the reaction temperature on the reforming performance and the coking behavior, two different reaction temperatures (800 and 900 °C) were investigated. At both temperatures the prepared catalyst showed high rates of CH4 consumption. The higher temperature promotes the stability of the catalyst performance due to mitigation of the carbon formation. [ABSTRACT FROM AUTHOR]

2-Propanol and oxygen were converted over titania and gold nanoparticles supported on titania to investigate the reactivity of the support, the influence of the metal and the role of metal-support interactions. The catalysts were characterized by N2 physisorption and transmission electron microscopy. In addition to deriving the degrees of conversion and the yields as a function of temperature, temperature-programmed desorption and diffuse reflectance infrared spectroscopy were applied in fixed-bed reactors under continuous flow conditions. Over pure TiO2 above 500 K the acid-base catalyzed dehydration yielding propene and water, the dehydrogenation to acetone and H2, and the oxidative dehydrogenation to acetone and water were found to occur. The additional presence of Au nanoparticles induced the selective oxidation to acetone and H2O at temperatures below 400 K, whereas the selective oxidation to acetone at higher temperatures above 500 K was also observed on pure TiO2. Also the dehydration of 2-propanol to propene and H2O and, to a minor extent, the total oxidation to CO2 and H2O were catalyzed by Au/TiO2. Therefore, the Au/TiO2 catalyst shows bifunctional properties in oxygen activation needed for the selective oxidation of 2-propanol. 2-propoxide species were detected by IR spectroscopy, which are identified as intermediate species in 2-propanol conversion, whereas strongly bound acetates and carbonates acted as catalyst poison for the selective low-temperature oxidation route, but not for the high-temperature route. Selective low-temperature oxidation is assumed to occur at the perimeter of the Au nanoparticles, which also enhance the high-temperature oxidation route on TiO2 pointing to a Mars-van Krevelen mechanism based on an enhanced reducibility of TiO2. [ABSTRACT FROM AUTHOR]

Abstract: Methanol oxidation was used as test reaction to investigate the influence of the metal, of the support, and of metal-support interactions in Au/ZnO and Au/TiO2 catalysts. Catalytic measurements as well as infrared spectroscopy were applied under continuous flow conditions in fixed-bed reactors. A strong effect of the Au loading ranging from 0.6wt.% to 1.9wt.% was found for both Au/ZnO and Au/TiO2 catalysts with Au particle sizes in the range from 3 to 7nm. Methanol combustion yielding H2O and CO2 was the main reaction path, but also reactions such as partial oxidation of methanol, steam reforming of methanol, methanol decomposition as well as the selective oxidation of methanol to methyl formate, formaldehyde, or dimethoxymethane were found to occur. Smaller Au particles and a higher amount of small Au particles had a beneficial effect on the activity. Infrared spectroscopy identified methoxy species adsorbed on the metal oxides as intermediates in methanol oxidation. The product distribution was found to depend on the oxide used as support due to the different Lewis acidities. On Au/TiO2, strongly bound formates acted as reversible catalyst poison. The catalytic activity was found to be correlated with the number of Au atoms at the perimeter of the Au nanoparticles. Correspondingly, oxygen activation is assumed to occur at their perimeter, and the oxide provides methoxy species reacting at the interface. [Copyright &y& Elsevier]

Keywords: CO2 hydrogenation; Energy conversion; Heterogeneous catalysis; Chemical battery; Cu/ZnO/Al2O3 EN CO2 hydrogenation Energy conversion Heterogeneous catalysis Chemical battery Cu/ZnO/Al2O3 3154 3154 1 06/22/20 20200618 NES 200618 B The Cover Feature b shows the concept of CO SB 2 sb hydrogenation as a chemical battery in the scope of a chemical energy conversion. In their Full Paper, H. Ruland et al. demonstrate the extraordinary stability and high performance of an industrial Cu/ZnO/Al SB 2 sb O SB 3 sb catalyst for methanol production from feed gases with high CO SB 2 sb concentrations. [Extracted from the article]