Influence of Ni/SiO₂ catalyst preparation methods on hydrogen production from the pyrolysis/reforming of refuse derived fuel

Hydrogen production from the pyrolysis/reforming of refuse derived fuel (RDF) was investigated with a series of Ni/SiO₂ catalysts. The catalysts were prepared by homogeneous precipitation derived from a sol-gel method (HPG) and compared to Ni/SiO₂ catalysts prepared by adding a phase separation step to the HPG process (B-HPG). All the catalysts had a NiO loading of 10 wt.%, and three different calcination temperatures (500 °C, 700 °C and 900 °C) were used for each method. The prepared Ni/SiO ₂ catalysts were analysed to determine their surface area, and porosity characteristics; additionally scanning electron microscopy (SEM-EDX), transmission electron microscopy (TEM), infrared spectroscopy (FTIR), and X-Ray diffraction (XRD) analyses were carried out. The results showed that the catalyst prepared by HPG and calcined at 700 °C (HPG700), presented a relatively high surface area (∼347 m² g^-1), large pore diameter (12.50 nm), and also resulted in the highest catalytic activity towards H₂ production, attaining ∼60 vol.% hydrogen. The lowest hydrogen concentration of about 42 vol.% was obtained using the catalysts prepared by the combined HPG-phase separation method, and calcined at 900 °C (B-HPG900). It was also observed that at calcination temperatures higher than 700 °C the catalytic activity for hydrogen production was diminished for both preparation methods.