Enhancing H₂ yield through NiO loading and process optimization in CO₂–CH₄ reforming over fibrous silica-ceria catalysts

The emerging global concern over climate change and the need for sustainable energy has led to extensive investigations into CO₂–CH₄ reforming as an efficient strategy for H₂ generation. Due to numerous challenges related to catalytic activity, this study focuses on the synthesis of NiO-impregnated fibrous silica–ceria (FSCe) support, generated through a microemulsion technique. The tests revealed that the 10 %Ni/FSCe catalyst exhibited the highest CO₂ (81.9–93.6 %) and CH₄ (92.9–99.6 %) conversion, as well as H₂ yield (46.7–58.9 %) across a temperature range of 500–800 °C, superior to the 5 %Ni/FSCe and 15 %Ni/FSCe. This is attributed to the great distribution of NiO on the FSCe support, preserving its fibrous morphology and maximizing the availability of active sites. XRD and FESEM confirm that NiO particles are well-dispersed, with no significant particle growth. CO₂-TPD analysis reveals that the 10 %Ni/FSCe catalyst has a favorable distribution of basic sites, particularly Lewis basic sites, which are crucial for CO₂ activation during the reforming process. Additionally, response surface methodology (RSM) was applied to the outperformed catalyst to optimize reaction conditions, identifying the ideal parameters for maximum H₂ yield (41.3 %). The experimental results closely match predicted values, thus validating the optimization model and confirming the high potential for sustainable H₂ production via CO₂–CH₄ reforming.