Deep oxidation of benzene over LaCoO3 catalysts synthesized via a salt-assisted sol-gel process

With the assistance of nitrate additives (KNO 3 , NaNO 3 , Ca(NO 3 ) 2 or Mg(NO 3 ) 2 ), perovskite LaCoO 3 , which has a 3D porous structure and relatively high surface area (around 20 m 2 /g) was successfully synthesized at 500 °C via a sol-gel process. The results of thermal gravimetric analysis indicated that nitrates (especially NaNO 3 and KNO 3 ) acted as combustion aids, which significantly lowered down the crystallization temperature of LaCoO 3 by intensifying the decomposition of organic ingredients. Unlike other researches, the metal ions from the nitrate additives did not dope into the crystal lattice of perovskite and it was found that the remained nitrate additives would dramatically inhibit the LaCoO 3 catalytic activity on benzene oxidation. However, after removal of these remained nitrate additives by rinsing with deionized water, LaCoO 3 derived from our proposed salt-assisted sol-gel method exhibited an excellent catalytic activity.