In this work, a series of metal carbonate minerals such as BaCO3, SrCO3, MnCO3, PbCO3 and CdCO3 with uniform and well-defined morphology were synthesized via the combination of regenerated silk fibroin (RSF) and compressed CO2. The as-prepared samples were systemically characterized by means of TEM, SEM, XRD, TGA and FTIR. The results showed the size, morphology, and nanostructure of crystals could be well controlled by altering the RSF concentration and crystallization time. Based on the time-resolved experiments, we found a spherical BaCO3 superstructure was formed by RSF chains induced stacking of needle-like units, following a “rod-to-dumbbell-to-twined sphere-to-sphere” morphological evolution process. In addition, both amorphous phase and a dissolution–recrystallization process of BaCO3 were observed in crystallization. Finally, a probable crystallization mechanism for the formation of spherical BaCO3 aggregates was proposed based on the experiments.

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