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The conversion of methane or natural gas into turquoise H2 and carbon represents a promising pathway towards decarbonised energy. The pyrolysis of biogas (mainly a mixture of methane and CO2) is considered to be a negative carbon-emission technology, as the carbon source comes from biomass and the carbon is captured in solid form. In addition, the presence of CO2 in the gas mixture enables the dry reforming of methane into syngas. In this study, we show that direct biogas conversion in a fluidised catalytic reactor can produce a syngas whose composition meets the requirements for methanol synthesis or for liquid hydrocarbon production via the Fischer-Tropsch process. Confirmed by thermodynamic analysis, we show that the reaction proceeds at temperatures above 900 1C to produce carbon materials, whereas at lower temperatures the carbon is converted to CO by the Boudouard reaction. At 950 1C, very high methane and CO2 conversions are achieved (490% and 99%, respectively), accompanied by high hydrogen yield (490%) and the sequestration of carbon into a turbostratic structure. We believe that the direct catalytic reforming of biogas in a fluidised bed, when combined in series with an FTS process, could allow the production of liquid fuels with no need for costly gas separation units, in particular those implemented for CO2 capture. [ABSTRACT FROM AUTHOR]

Cu/ZrO2 is a promising catalyst for the hydrogenation of CO2 to methanol. Reaction pathways involving formates or hydroxycarbonyls have been proposed. We show here that three different types of formates can be observed under reaction conditions at 220 °C and 3 bar, one being located on metallic Cu and two others being bound to ZrO2. The surface concentrations of formates were determined through calibration curves and their reactivity measured during chemical transient experiments. The Cu‐bound formate represented only about 7 % of surface formates, but exhibited a higher reactivity and was found to be the only formate that could account for all the production of methanol. Copper is thus not there only to activate H2, but also bears other crucial intermediates. This work reemphasizes that fully quantitative IR analyses and transient methods are required to unravel the role of surface species. [ABSTRACT FROM AUTHOR]

Cu/ZrO2 is a promising catalyst for the hydrogenation of CO2 to methanol. Reaction pathways involving formates or hydroxycarbonyls have been proposed. We show here that three different types of formates can be observed under reaction conditions at 220 °C and 3 bar, one being located on metallic Cu and two others being bound to ZrO2. The surface concentrations of formates were determined through calibration curves and their reactivity measured during chemical transient experiments. The Cu‐bound formate represented only about 7 % of surface formates, but exhibited a higher reactivity and was found to be the only formate that could account for all the production of methanol. Copper is thus not there only to activate H2, but also bears other crucial intermediates. This work reemphasizes that fully quantitative IR analyses and transient methods are required to unravel the role of surface species. [ABSTRACT FROM AUTHOR]