Facile synthesis of Ni-M/MgO (M=Y₂O₃, Gd₂O₃) catalysts using the surfactant-assisted co-precipitation method and their applications in the methane decomposition reaction

This paper describes the properties and performance of the Ni/MgO catalysts fabricated via the surfactant-aided co-precipitation technique by diverse precipitants like PVA, CTAB, and PVP. Among the surfactants adopted, PVA was the most effective and indicated a high catalytic potential of about 60 % at 600 °C with GHSV of 24,000 mL/g.h. The XRD, BET, SEM-EDX, H₂-TPR, TPO, and Raman techniques were extensively applied to estimate the structural properties of the as-prepared catalysts. The other goal of this study was the evaluation of the effect of the promotion of Ni-based catalysts by selected rare earth metals, Y (2.5 5, 10 wt%) and Gd, on the activity of Ni/MgO catalyst in the methane decomposition process, which has not been widely investigated in this process. The obtained results revealed that the Gd promoter did not provide structural and performance advantages. The results of the BET area related to the introduction of promoters showed that the 50Ni-5Y/MgO catalyst possesses a large surface area (64.7 m²/g), low pore size (13.8 nm), and crystal size (16.1 nm). The result also displays that a maximum CH₄ conversion of about 75 % was obtained for this sample at 675 °C and has an excellent lifetime in 300 min of reaction. In addition, the Raman spectra indicated the attendance of the ordered filamentous carbon with nice crystallinity on the bed of the 50Ni-5Y/MgO.