CO2 reforming of biodiesel-waste glycerol on nanostructure Ni-SiO2.MgO catalysts for syngas production: Influence of the catalyst chemical composition

[Display omitted] •xNi-ySiO2.MgO is made using a one-step method as a catalyst for syngas production.•Catalyst composition significantly influenced characteristics and reforming activity.•10Ni-SiO2.MgO catalyst possessed the highest glycerol conversion of 50% at 750 °C.•MgO addition influenced carbon deposition nature. This study investigated the potential of CO2 reforming of biodiesel-waste glycerol for synthesis gas (syngas) production using xNi-ySiO2.MgO catalysts. Catalysts were prepared with varying nickel loading and SiO2 to MgO ratios (0.5–2) using a one-step synthesis route. The catalysts exhibited a high BET surface area of 545 m2 g−1. The impact of catalyst composition, including nickel content and SiO2 to MgO ratio, on the physicochemical characteristics and catalytic behavior during glycerol CO2 reforming was examined. Catalytic performance evaluation revealed that the catalyst with a SiO2/MgO molar ratio of 1:1 and the highest nickel content (8.01 wt%) displayed the best activity (50 % glycerol conversion at 750 °C) and stability under harsh reforming conditions (GHSV = 7.2 × 104 mL h−1 gcat-1). This catalyst had a small crystalline size (8.5 nm) and a higher degree of NiO reduction, as confirmed by TPR and XRD analysis. In contrast, the Ni-SiO2 catalyst exhibited poor catalytic behavior due to lower reducibility and metal dispersion. Encapsulated carbon formation further reduced its catalytic performance. The combination of SiO2 and MgO in the Ni-based catalysts synergistically improved their catalytic performance. The results emphasize the importance of catalyst composition, including nickel content and SiO2 to MgO ratio, in determining the physicochemical properties and catalytic behavior during glycerol dry reforming. In conclusion, CO2 reforming of biodiesel-waste glycerol using xNi-ySiO2.MgO catalysts shows promise for sustainable syngas production. The findings contribute to the utilization of glycerol waste and offer opportunities for reducing environmental impact through efficient conversion into valuable syngas.