Barium Carbonate Synthesized via Hydrolysis: Morphostructural Analysis and Photocatalytic Performance in Polymer and Geopolymer Matrices

Barium carbonate (BaCO3) nanoparticles were synthesized by a facile hydrolysis route using BaCl2 and KOH in aqueous solution, with atmospheric CO2 as the carbonate source, without external agents. Their structural and morphological properties were investigated by XRD, ATR-FTIR, SEM, and BET, confirming the formation of a pure orthorhombic witherite phase with rod-like morphology and different surface specific areas. The crystallite size increased from 52 to 86 nm with higher precursor concentration and synthesis temperature, as predicted by a regression model correlating synthesis parameter with particle growth. When incorporated into polymer (PVC) and geopolymer (GP) matrices, BaCO3 enhanced the photocatalytic degradation of methylene blue (MB) under solar light, with GP@Nano-BaCO3 achieving a higher rate constant compared to PVC@Nano-BaCO3. The results highlight that the synthesis strategy yields well-defined BaCO3 nanoparticles with tunable structural features and promising photocatalytic potential when integrated in functional polymer matrices. Future work will address doping strategies and testing in real wastewater conditions. Overall, this synthesis strategy offers a reproducible and environmentally friendly route to BaCO3 nanoparticles with potential applications in hybrid materials for visible light-driven environmental remediation.