Selective Fabrication of Barium Carbonate Nanoparticles in the Lumen of Halloysite Nanotubes

Barium carbonate (BaCO3) materials with the controllable morphology of nanoparticles were selectively loaded into the lumen halloysite nanotubes (abbreviated as Hal) by a urease assisted catalytic implementation strategy. The Hal mineral was pre-treated through leaching by hydrochloric acid (abbreviated as A-Hal), resulting in increased defect sites and zeta potential. The negatively charged urease was loaded inside the positively charged A-Hal lumen, and then through the decomposition of urea catalyzed by urease to produce carbonate ions and ammonia. When Ba2+diffused in, BaCO3particles were selectively synthesized in the lumen of A-Hal, the pore channels of A-Hal effectively controlled the growth and aggregation of BaCO3nanocrystals and their geometrical morphology. The obtained BaCO3/A-Hal-T was characterized by transmission electron microscopy, Fourier transformation infrared spectroscopy and X-ray diffraction, differential scanning calorimetry-thermogravimetry (DSC-TG). The BaCO3/A-Hal-T may provide a candidate for potential applications.Keywords:halloysite;urease;barium carbonate;selective decoration;nanoreactors