Silver morphology indicating the evolution of concentration heterogeneity

Heterogeneity is the main problem of scaleups. The common strategy to solve this problem is the enhancement of transport. Here we show an alterative by figuring out the role of heterogeneity and then controlling the heterogeneity for desired products. We employed a gel system to create a diffusion limitation and to discover how the local concentration heterogeneity influences the shape development of silver particles in an electrochemical synthesis process. An interesting phenomenon was observed that the shapes of silver particles were dependent on their location. Silver dendrites were synthesized around the electrode, while polycrystalline spheres were obtained at the forward growth front. The mixture of dendritic and spherical particles was observed between the electrode and the growth front. A temporal evolution of concentration heterogeneity was proposed to interpret the dependence of particle morphology with location. This interpretation was confirmed by regulating the concentration distribution in different gel systems and at different reaction rates. This paper showed that the concentration distribution plays a significant role in the shape development of particles, and controlling the local heterogeneity promises an alternative for the rational synthesis of materials