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

Abstract With the assistance of nitrate additives (KNO3, NaNO3, Ca(NO3)2 or Mg(NO3)2), perovskite LaCoO3, which has a 3D porous structure and relatively high surface area (around 20 m2/g) was successfully synthesized at 500 °C via a sol-gel process. The results of thermal gravimetric analysis indicated that nitrates (especially NaNO3 and KNO3) acted as combustion aids, which significantly lowered down the crystallization temperature of LaCoO3 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 LaCoO3 catalytic activity on benzene oxidation. However, after removal of these remained nitrate additives by rinsing with deionized water, LaCoO3 derived from our proposed salt-assisted sol-gel method exhibited an excellent catalytic activity.