Tuning the Stability and Crystallization Pathway of Georgeite via Solution Parameters

Abstract

Amorphous phases typically serve as pivotal intermediates in biomineralization and functional materials synthesis due to their high reactivity and metastability. However, the stability and crystallization pathways of amorphous phases depend on many factors and are difficult to control. Amorphous basic copper carbonate (ABCC), or georgeite, is a key precursor of basic copper carbonate (BCC) and other copper-based functional materials with great potential for application. In this work, combining various in situ and ex situ characterization techniques, a comprehensive view on the stability and crystallization pathways of ABCC is provided. The results indicate that the structure and particle size of ABCC prepared at different initial concentrations are slightly different, which drastically influence their thermal stability under heating in air. Furthermore, the transformation from ABCC to BCC in aqueous solution proceeds via the attachment of nanoparticles, where the interfacial structural rearrangement during aggregation dominated the crystallization kinetics. This observations challenge the classical view of crystallization that nucleation barrier or the supersaturation controls the crystallization kinetic. This study can help researchers further understand the crystallization mechanism from amorphous to crystalline phase and provide guidance for stabilizing the amorphous phase.