Polymer-assisted dispersion of Ni on Zirconia through non-hydrolytic sol-gel method

Christine Warwar Damouny, Chemical Engineering, Technion, Haifa, Israel
Christine Khoury, Chemical Engineering, Technion, Haifa, Israel
Oz Gazit, Chemical Engineering, Technion, Haifa, Israel

Nickel-based catalysts have been identified as highly active catalysts for dry reforming of methane, to make synthesis gas (CO +H2). Unfortunately, the Ni catalytic sites deactivate due to carbon deposits during reaction (i.e. coke formation). It has been reported that smaller Ni particles (1-3 nm) are more resistant to coke formation. However, obtaining such small dimensions and moreover to keep them from sintering under the high temperatures of the reaction (>700ᴼC) has proven to be a difficult task. Encapsulating the Ni nanoparticles in a 3D porous support can form a highly dispersed Ni catalyst with higher stability and better catalytic performance. In this work, we develop a general methodology to make Ni nanoparticles within a porous ZrO2 support. This is achieved by combining chitosan, a natural polymer, for dispersing the Ni precursor followed by its encapsulation using a non-hydrolytic sol-gel route (NNSG). Our results show that the obtained Ni@ZrO2 samples are highly porous, with tetragonal-stable phase at elevated temperatures up to 800ᴼC, with Ni dispersions around 11%. Surface area is shown to increase up to 144m2/g with the increase in the polymer content during the sol-gel process. The samples were characterized by FT-IR, HR-SEM, EDS, XRD, N2-Physisorption, and chemisorption analysis.