The aim of the project is the development of new active, selective and robust catalysts for syngas (H2+CO) production by the catalytic partial oxidation of methane (CH4-CPO). The research program will be focused on the preparation, the characterization and the study of catalytic activity of nanostructured ZrO2-supported Ni systems that showed in preliminary tests a promising activity and stability for CH4-CPO. Ni/ZrO2 samples at various Ni loading (0.5-5.0 wt%) will be prepared by using ZrO2 support with different morphology and characterized by the combined use of different chemical-physical techniques (XRD, UV-vis, SEM, FTIR, Raman, XPS and porosimetry measurements). Catalytic study will be performed in a flow apparatus at atmospheric pressure in steady state conditions with a CH4+O2 mixture, by changing feed ratio, reaction temperature, contact time and catalyst pre-treatment.
The comparison between the results of characterization and those of catalytic studies is aimed at understanding the relationship between composition, structure and catalytic properties of the materials. Beside this, characterization results on Ni/ZrO2 catalysts will be compared with those of unsupported Ni in order to clarify the nature of the metal-support interaction and its role in stabilizing the nano-structures against sintering in the reaction conditions.
The following points will deserve special attention:
i) the role played by preparation methods and activation conditions (temperature, atmosphere) on the dispersion of the active phase;
ii) the effect of Ni particle size and ZrO2 crystallographic modifications on the catalytic performances
iii) the conditions that lead to deactivation and the structural properties of deactivated species;
iv) the structural and morphological properties of the systems after catalytic tests.
Some theoretical calculation will be used to understand the nature of the possible transition states and intermediates involved in the reaction pathway.
