Abstract: Calcium-based sorbent is widely applied in sorption enhanced steam methane reforming for hydrogen production. However, its practical application is constrained by the gradual degradation of sorption capacity and reaction kinetics during cyclic operations. Although our preliminary studies demonstrated that CaZrO3 dopant significantly enhances the stability of adsorption performance, the underlying mechanism remains unclear. A multi-physics coupling model of the carbonation process of calcium-based sorbents was established, incorporating experimentally characterized structural parameters to investigate the effect of CaZrO3 dopant on CO? diffusion and the mechanism for improving sorption stability. The model integrates the changing grain size mode with transient heat and mass conservation equations. The results indicate that CaZrO3 dopant (40 wt% CaZrO3) helps maintain the