Kinetics and Mechanism of Ni/La-Promoted Fibrous Silica Titania (FST) for High-Performance Syngas Generation via Dry Reforming of Methane

Abstract This study investigates the dry reforming of methane using a lanthanum-promoted nickel catalyst supported on fibrous silica–titania (La-Ni/FST). The catalyst was synthesized through a micro-emulsion and TiO 2 seed crystallization process, followed by the incipient wetness impregnation method for Ni loading and La promotion. Comprehensive characterization was performed using N 2 physisorption, FESEM, H 2 -TPR, CO 2 -TPD, FTIR-KBr, and XRD techniques. The La-Ni/FST catalyst demonstrated a high surface area of 284.20 m 2 /g and a mesoporous structure, which enhanced the dispersion of active sites and the accessibility of reactants. The catalytic performance was evaluated at temperatures ranging from 550 to 850 °C in a fixed-bed reactor. The catalyst achieved nearly complete CH 4 conversion (99.8%) and a high CO 2 conversion (93.4%) at 850 °C, with an optimal H 2 /CO ratio of approximately 1.0, indicating its suitability for Fischer–Tropsch synthesis. Stability tests conducted over 72 h confirmed sustained activity with minimal deactivation. Kinetic modelling using both power law and Langmuir–Hinshelwood (LH) models identified CH 4 dissociation as the rate-determining step. The LH Model 5, which considers the dissociative adsorption of CH 4 and CO 2 on a single active site, best described the reaction kinetics. Raman spectroscopy and TEM analysis revealed moderate graphitic carbon deposition (id/ig = 0.92), suggesting enhanced resistance to coke formation. This study highlights the effectiveness of La promotion in improving the stability and performance of the Ni catalyst for sustainable syngas production, emphasizing its potential for industrial DRM applications.