The CASiBIO project aims to develop porous Ni(Ru)/SiCxOy catalytic ceramics for dry methane reforming and CO2 methanation reactions, two key reactions in the energy field for which catalyst stability is the main issue.The Polymer Impregnation Pyrolysis (PIP) process is selected to synthesise these objects because it allows for an easy control of the chemical composition (from SiC carbide, to oxycarbide, SiCxOy) and the shaping of the ceramic. To generate the porosity within the material, preforms based on lignocellulosic fibres (LF) will be used. These preforms are selected for their biobased nature, abundance, biodegradability, and ease of chemical modification. We will use paper pulp from the Kraft process, composed of approximately 85% cellulose, which makes it possible to adopt an eco-responsible scientific approach both in the choice of precursors and in the process of shaping the objects. On the surface of these objects, the composition of the SiCxOy support is modulated to optimise heat transfer during catalytic reactions (highly exothermic reaction for methanation; conducted at high temperature for reforming). The project proposes to elucidate the mechanisms of FL - preceramic polymer interactions, and their impact on the final properties of the ceramics. The effect of the method of incorporation of the catalytic elements, Ni(Ru) and dopants (A = ZrO2, CeO2, MgO, TiO2, Al2O3), will also be studied. In this perspective, a coherent and complementary combination of structural and microstructural characterisations (SEM-FIB, EELS-EDS-STEM, X-ray tomography, DRX) and physico-chemical investigations (rheology of precursors, IR, NMR, XPS spectroscopies, porosimetry) is proposed. The geometric modelling of the objects developed, based on fine microstructural characterisations, will allow the 3D visualisation of the fluid simulations carried out in order to evaluate the mass transfers. After optimisation (support and active phases), the Ni(Ru)-A/SiCxOy catalysts will be tested for methanation and methane reforming reactions. The assessment of the catalytic performances will be carried out under conditions close to the real operating conditions, by determining the impact of recurrent poisons (H2S, NH3) and of the reaction duration on the performances of the catalytic ceramics. These data sets will lead to the establishment of the microstructure/catalytic properties relationships of these complex materials. This multidisciplinary project associates 4 research laboratories with complementary skills: (i) the Institute of Research for CERamics (IRCER) for the development and characterisation of porous ceramics from functionalised LFs; (ii) XLIM, ffor the implementation of the modelling and visualisation approach of the objects, as well as for the realization of computer simulations; (iii) the Catalysis and Solid State Chemistry Unit (UCCS) for the optimisation of the catalytic formulation in terms of composition and dispersion; (iv) the Environmental Chemistry and Interactions with the Living Environment Unit (UCEIV) for the measurement of catalytic activity (reforming reaction, methanation) and the determination of the deactivation mechanisms of the catalysts.