Synthesis of Cobalt Nano Particles on Silica Support Using the Strong Electrostatic Adsorption (SEA) Method

Abstract

Supported cobalt is one of the common catalysts used in Fischer-Tropsch synthesis (FTS). Strong electrostatic adsorption (SEA) was employed to synthesize cobalt nano particles supported on silica. Cobalt nitrate was used as the catalyst precursor and non-porous silica spheres, which were synthesized using the modified Stöber method, were used as a catalyst support. Point of zero charge (PZC) for silica was determined using equilibrium pH at high oxide loading (EpHL) method. The optimum pH was determined by measuring cobalt uptake versus pH. High cobalt uptake at basic pH and low cobalt uptake at acidic pH indicates electrostatic interaction between the cobalt complexes in the precursor solution and the hydroxyl group on the support’s surface. Catalysts prepared at optimum pH were characterized using TPR, XPS and TEM. TPR shows reduction peak at high temperature (587°C) indicating strong interaction between cobalt and silica support. XPS shows presence of Co2+ species on the surface. TEM images of the Co/SiO2 at 5 wt% and 10 wt% cobalt loadings show fairly well-dispersed cobalt oxide nano particles on the spherical silica support with narrow particle size distribution. The findings suggest that SEA was deemed a suitable method to prepare supported cobalt catalysts.

Acidic/Basic Oxides-Supported Cobalt Catalysts for One-Pot Synthesis of Isophorone Diamine from Hydroamination of Isophorone Nitrile

“…The Co 2p spectrum also had a weak Co 2p 3/2 peak at 780.2 eV and a weak Co 2 P 1/2 peak at 795.2 eV, which were attributed to the Co II 2p 3/2 and Co II 2p 1/2 configuration. The weak peaks at 783.4 and 798.2 eV represented the shakeup peaks for Co II 2p 3/2 and Co II 2p 1/2 , respectively, which were the important fingerprints of CoO to distinguish it from the other forms of cobalt. ,,− …”