Enhanced syngas generation from CO₂ and CH₄: A sustainable approach using Zr-promoted Ni/POFA-SBA-15 for environmental benefit

This study presents a sustainable strategy for enhancing syngas production through the catalytic conversion of CH₄ and CO₂ using a Zr-promoted Ni-based catalyst supported on SBA-15 synthesized from palm oil fuel ash (POFA), an abundant agro-industrial waste. POFA offers an eco-friendly and cost-effective alternative to conventional silica sources such as tetraethyl orthosilicate. The Ni-Zr/POFA-SBA-15 catalyst was prepared via incipient wetness impregnation method and characterized using XRD, FESEM, and N₄ physisorption analyses. Zirconium incorporation improved Ni dispersion and reduced metal particle size, leading to enhanced catalytic activity. A two-step statistical design approach was applied to maximize methane dry reforming (MDR) performance. Initially, a 2-level factorial design was used to identify significant parameters, followed by a rotatable central composite design tool of response surface methodology (RSM) for optimization. The effects of CH₄/CO₂ ratio (0.5–1.5), reaction temperature (650–850 °C), and time on stream (TOS) (60–240 min) were examined. The screening results demonstrated that all 3 parameters impact MDR performance. The optimum conditions, as determined by RSM, were 811.86 °C, a CH₄/CO₂ ratio of 1.46, and a 90 min TOS, resulting in 80.41 % CH₄ conversion, 97.37 % CO₂ conversion, and an H₂/CO ratio of 0.95. The experimental validation under these conditions closely matched RSM predictions, with negligible deviation. The catalyst demonstrated excellent thermal stability with only 10.08 % activity loss after 30-h of continuous operation. These findings highlight the potential of POFA-derived SBA-15-supported catalysts as a cost-effective and sustainable option for long-term syngas production.