Kinetics and deactivation modelling of fibrous silica-supported Ni-Ga catalysts for COx-free hydrogen production via methane splitting

Thermocatalytic methane splitting offers a viable route for hydrogen production without greenhouse gas emissions. In this study, a detailed kinetic and deactivation analysis was conducted for methane splitting over a Ni–Ga/KCC1 catalyst using a fixed-bed reactor at temperatures ranging from 600 to 650 °C and varying methane partial pressures (0.2–0.8 atm). Structure–activity correlations were explored via characterization of fresh and spent catalysts using X-ray diffraction (XRD), nitrogen physisorption, hydrogen temperature-programmed reduction (H 2 -TPR), Transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The intrinsic reaction kinetics revealed a reaction order of 0.56 and an activation energy of 62.16 kJ mol −1 . Catalyst deactivation behavior was systematically investigated using two modeling approaches: the Power-Law Model (PLM) and the Exponential Decay Model (EDM). However, EDM provided an overall better fit compared to PLM. Based on decay model parameters (A and τ), the activity factor was quantitatively modeled as a function of methane partial pressure and reaction temperature, showing strong agreement with experimental data. This work establishes a comprehensive kinetic and deactivation framework for Ni–Ga/KCC1-catalyzed methane splitting, providing predictive insights for hydrogen production under varied process conditions.