Response surface methodology for optimizing the activity of bimetallic Ni–Co–Ce/Al2O3 catalysts in the steam methane reforming
Fatemeh Zarei-Jelyani, Fatemeh Salahi, Maryam Meshksar, M. Farsi, Mohammad Reza Rahimpour
Abstract
Hydrogen is being explored as a potential energy carrier for power and heat production, as well as energy storage, making it one of the most significant basic chemicals. In this work, steam methane reforming (SMR) over Ce-promoted Co–Ni/Al 2 O 3 catalysts were employed to produce hydrogen , and the response surface method (RSM) based on an optimal custom method was used to examine the interplay between synthetic and operational factors affecting methane conversion, hydrogen yield and H 2 /CO molar ratio . Several independent factors were considered, including the catalyst Co/Ni mass ratio (0, 0.5, 1), Ce loading (0, 1.5, 3.0), operation temperature (600, 650, 700 °C), steam to methane (S/M) molar ratio (1.5, 2.5, 3.5), and support type (bulk and hollow Al 2 O 3 ). Among the two determined optimized results in Design Expert, the hollow 0.17Co–Ni-1.26Ce@Al 2 O 3 catalyst was the best choice, depicting 96.20% methane conversion, 96.89% hydrogen yield and 6.57H 2 /CO molar ratio. The stability test of both hollow and bulk optimized catalysts was compared in optimal conditions (S/M molar ratio and temperature) over a 12-h SMR reaction. The physical properties and morphology of the optimized catalysts were determined before and after the steam reforming reaction using FESEM , XRD , N 2 physisorption , TPR, and TGA analyses.