Top-down fabrication of porous metal silicate nanoparticles from chemobrionic chemical gardens.

Porous inorganic nanoparticles are pivotal across the chemical, biomedical, and energy sectors. However, conventional synthesis methods typically rely on expensive organic templates and energy-intensive, high-temperature calcination steps. Although chemobrionic systems offer a sustainable route toward self-assembled architectures, their top-down processing into functional nanomaterials remains largely unexplored. Here, we present a facile and template-free strategy to synthesize functional metal-silicate nanoparticles by disintegrating alkaline-earth, transition, and rare-earth chemical gardens via sonochemical processing under ambient conditions. Controlled precursor growth was achieved by direct injection of the reactants to optimize synthesis parameters. By maintaining a constant silicate-to-cation ratio (1.0 M : 0.5 M) across distinct metals (Ca2+, Co2+, and Eu3+), we demonstrate that modulating the physicochemical properties and identity of the constituent cation directly tunes the pore architecture and surface properties of the resulting matrices. Comprehensive bulk compositional and structural characterization tracking revealed that high-energy acoustic cavitation drives a simultaneous mechanical disintegration and chemical purification process, selectively leaching labile metal hydroxide secondary phases entrapped within the macroscopic precursor channels to yield stable, highly porous metal-silicate networks with verified structural integrity. Finally, the broad versatility of these nanoparticles was validated through three tailored applications dictated by the metal's intrinsic properties: calcium-based nanoparticles demonstrated robust stability and protective capacity against erosion under simulated oral microenvironments; cobalt-based variants acted as viable electrocatalysts for the oxygen evolution reaction, and europium-containing nanoparticles demonstrated near-zero cytotoxicity, proving highly suitable as fluorescent biomarkers for biomedical imaging. This universal top-down strategy underscores the potential of chemobrionic-derived materials as highly adaptable platforms for advanced nanotechnology.