C1 chemistry, reactions involving one-carbon containing molecules such as CO, CH4 and CO2, is expected to play even more vital roles for future chemical industries and environmental protection. This doctoral thesis describes novel reactor concepts and operando analytical methodologies to understand and innovate three C1 chemistry of future importance, namely oxidative coupling of methane (OCM), CO2 capture and reduction (CCR) to methane, and dry reforming of methane (DRM). For OCM, spatiotemporal investigation of physicochemical gradients of gaseous concentration, catalyst temperature and coking behavior present in the catalytic reactor under harsh conditions (up to ca. 1000 °C) clarifies distinct reaction mechanisms ruled by the nature of the catalyst materials used. Strikingly, unselective homogeneous reactions taking place in the gas phase are shown to be induced by the explosive oxidation of hydrogen produced via partial oxidation of CH4. Such unfavorable reaction paths can be suppressed by the use of promoters which modify the catalyst surface, thereby drastically improving the product selectivity towards C2 molecules (ethane and ethylene) against CO and CO2. Secondly, a novel CCR strategy for CO2 methanation based on unsteady-state operation is developed using Ni-based catalysts. The effects of two promoters, K and La, on CO2 capture capacity, reduction rate and reaction mechanisms are unraveled by means of spatiotemporal operando diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Finally, the potential of unsteady-state operation and looping concept are explored for DRM using Ni-based catalysts, clarifying the critical roles of support materials, promoters and reaction temperature on CH4 decomposition, coke formation and coke oxidation by CO2.

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