Catalytic Design of Matrix-Isolated Ni/Chitosan Composites for Methane Decomposition

Targeted synthesis of Ni/C-containing composite materials was carried out using the matrix isolation method. The Ni content was varied (5-20 wt.% from chitosan). The morphology and physicochemical properties of the obtained materials were characterized using a number of methods: elemental analysis, SEM, TEM, XRD, FTIR, Raman spectroscopy, TPR-H₂, and SSA. FTIR showed that nickel ions are immobilized on the chitosan molecule, and heat treatment of the polymer molecule results in the formation of polyconjugation centers. It was also revealed that heat treatment of the salt-polymer films results in the formation of a graphite-like structure (Raman spectroscopy) with the inclusion of nickel in metallic form (XRD, TPR-H₂), with a particle size from 2 to 10 nm (TEM). The composites were shown to have a SSA of up to 269 m²/g. The resulting composite materials were used as catalysts for the decomposition of methane to produce hydrogen. High activity was observed in the catalytic methane decomposition at 700 °C (methane conversion up to 25.8%; hydrogen yield up to 1.98 g_H2/g_Ni/h).