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Direct conversion of methane with carbon dioxide to value‐added chemicals is attractive but extremely challenging because of the thermodynamic stability and kinetic inertness of both molecules. Herein, the first dinuclear cluster species, RhVO3−, has been designed to mediate the co‐conversion of CH4 and CO2 to oxygenated products, CH3OH and CH2O, in the temperature range of 393–600 K. The resulting cluster ions RhVO3CO− after CH3OH formation can further desorb the [CO] unit to regenerate the RhVO3− cluster, leading to the successful establishment of a catalytic cycle for methanol production from CH4 and CO2 (CH4+CO2→CH3OH+CO). The exceptional activity of Rh‐V dinuclear oxide cluster (RhVO3−) identified herein provides a new mechanism for co‐conversion of two very stable molecules CH4 and CO2. [ABSTRACT FROM AUTHOR]

Abstract: The single copper atom doped clusters CuAl4O7–9− can catalyze CO oxidation by O2. The CuAl4O7–9− clusters are the first group of experimentally identified noble‐metal free single atom catalysts for such a prototypical reaction. The reactions were characterized by mass spectrometry and density functional theory calculations. The CuAl4O9CO− is much more reactive than CuAl4O9− in the reaction with CO to generate CO2. One adsorbed CO is crucial to stabilize Cu of CuAl4O9− around +I oxidation state and promote the oxidation of another CO. The widely emphasized correlation between the catalytic reactivity of CO oxidation and Cu oxidation state can be understood at the strictly molecular level. The remarkable difference between Cu catalysis and noble‐metal catalysis was discussed. [ABSTRACT FROM AUTHOR]

Abstract: The underlying mechanism for non‐oxidative methane aromatization remains controversial owing to the lack of experimental evidence for the formation of the first C−C bond. For the first time, the elementary reaction of methane with atomic clusters (FeC3−) under high‐temperature conditions to produce C−C coupling products has been characterized by mass spectrometry. With the elevation of temperature from 300 K to 610 K, the production of acetylene, the important intermediate proposed in a monofunctional mechanism of methane aromatization, was significantly enhanced, which can be well‐rationalized by quantum chemistry calculations. This study narrows the gap between gas‐phase and condensed‐phase studies on methane conversion and suggests that the monofunctional mechanism probably operates in non‐oxidative methane aromatization. [ABSTRACT FROM AUTHOR]

Identification and mechanistic study of thermal methane conversion mediated by gas-phase species is important for finding potentially useful routes for direct methane transformation under mild conditions. Negatively charged oxide species are usually inert with methane. This work reports an unexpected result that the bi-metallic oxide cluster anions PtAl2O4− can transform methane into a stable organic compound, formaldehyde, with high selectivity. The clusters are prepared by laser ablation and reacted with CH4 in an ion trap reactor. The reaction is characterized by mass spectrometry and density functional theory calculations. It is found that platinum rather than oxygen activates CH4 at the beginning of the reaction. The Al2O4− moiety serves as the support of Pt atom and plays important roles in the late stage of the reaction. A new mechanism for selective methane conversion is provided and new insights into the surface chemistry of single Pt atoms may be obtained from this study. [ABSTRACT FROM AUTHOR]

Die gemeinsame katalytische Umsetzung von Methan mit Kohlendioxid zur Erzeugung von Synthesegas (2 H2+2 CO) umfasst komplizierte Elementarschritte, und fast alle Elementarreaktionen werden praktisch bei den gleichen Hochtemperaturbedingungen der Thermokatalyse durchgeführt. Hier zeigen wir durch massenspektrometrische Experimente, dass RhTiO2− die gemeinsame Umsetzung von CH4 und CO2 zu freiem 2 H2+CO und einem adsorbierten CO (COads) bei Raumtemperatur fördert; der einzige Elementarschritt, der die Zufuhr von externer Energie erfordert, ist die Desorption von COads vom RhTiO2CO− zur Rückbildung von RhTiO2−. Die aktuelle Studie identifiziert nicht nur eine vielversprechende aktive Spezies für die Methan‐Trockenreformierung (CO2‐Reformierung) zu Synthesegas, sondern unterstreicht auch die Bedeutung der Temperaturkontrolle über Elementarschritte in der angewandten Katalyse, die die Kohlenstoffabscheidung durch Methanpyrolyse erheblich mindern könnte. [ABSTRACT FROM AUTHOR]

Abstract: The single copper atom doped clusters CuAl4O7–9− can catalyze CO oxidation by O2. The CuAl4O7–9− clusters are the first group of experimentally identified noble‐metal free single atom catalysts for such a prototypical reaction. The reactions were characterized by mass spectrometry and density functional theory calculations. The CuAl4O9CO− is much more reactive than CuAl4O9− in the reaction with CO to generate CO2. One adsorbed CO is crucial to stabilize Cu of CuAl4O9− around +I oxidation state and promote the oxidation of another CO. The widely emphasized correlation between the catalytic reactivity of CO oxidation and Cu oxidation state can be understood at the strictly molecular level. The remarkable difference between Cu catalysis and noble‐metal catalysis was discussed. [ABSTRACT FROM AUTHOR]