Optimization and modelling of the supercritical CO2 deposition of CoxOy nanoparticles in MCM41

ASPROMONTE, SOLEDAD; SASTRE, ALVARO; BOIX, ALICIA V.; COCERO, MARÍA JOSÉ; ALONSO, ESTHER

JOURNAL OF SUPERCRITICAL FLUIDS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 110 p. 47 - 55

0896-8446

Nanocomposites of cobalt oxide on mesoporous silica support (Co/MCM41) have been synthesized by supercritical fluid reactive deposition (SCFRD) with cobaltocene (CoCp2) as cobalt precursor. Dissolution of CoCp2 in scCO2 and adsorption onto MCM41 has been performed at 70 ºC and 11.0 MPa. Under these conditions the adsorbed CoCp2 is 7.7 g/kg after 3 h and is negligible for times shorter than 2 hours. Thus, a thermal decomposition of precursor is performed in order to obtain higher loading of active phase. A temperature of 200 °C has been selected for the decomposition of CoCp2 according to FTIR and TGA analysis, and the decomposition time (from 1 to 3 h) has not any effect on the cobalt loading. The maximum content of cobalt takes place at a pressure of 15 MPa during the decomposition step. The composite material with 4.3 wt. % Co has a BET surface area of 1034 m2/g, a pore size of 3.9 nm and metal nanoparticles of 20-30 nm.