Size-Controlled Synthesis of CuO Nanoparticles by the Supercritical Antisolvent Method in SBA-15

Herein, we describe a facile method to control the size and dispersion of CuO nanoparticles (NPs) in SBA-15 by the supercritical antisolvent (SAS) method during the depressurization process of supercritical fluid deposition (SCFD), describing the mass transfer between supercritical carbon dioxide (scCO(2)) and a cosolvent. On reducing the concentration of the cupric nitrate precursor, the size of CuO NPs was decreased from 3.5 +/- 1.0 to 1.0 +/- 0.4 nm (Cu loading 14.2-12.1 wt %) under the depressurized rate of similar to 20 MPa/min. Based on the size distribution and nucleation theory, the nucleation rate of the precursor could reach 10(25) cm(-3).s(-1), and the calculated interface energy of cupric nitrate was less than 0.1 J/m(2), indicating that scCO(2) as an antisolvent caused the heterogeneous nucleation of the precursor on the surface of SBA-15 channels. Hence, the nucleation rate and growth of cupric nitrate were regulated under a given scCO(2) depressurized rate, and then the CuO NPs' size distribution and Cu loading were controlled subsequent to calcination.

Automated summary

In this study, a facile method to control the size and dispersion of CuO nanoparticles in SBA-15 using supercritical antisolvent method was described. By reducing the concentration of the cupric nitrate precursor, the size of CuO NPs was decreased and the Cu loading was controlled under a given depressurized rate. The nucleation rate and growth of cupric nitrate were regulated by adjusting the supercritical carbon dioxide depressurized rate.