Hard-NaCl template-regulated LiCoO2 catalyst with enhanced activity for aqueous and gaseous organics elimination

Abstract

Developing new and effective catalytic materials is of significant importance to the catalytic oxidation of multiphase organic pollutants. In the present work, lithium cobalt oxide (LiCoO2) was synthesized and modified via hard-NaCl template regulation for the oxidative elimination of organic dye, e.g. rhodamine B (RhB), and VOCs, e.g. benzene. Compared with the pristine sample, a medium-level NaCl addition offered a much more advanced reactivity towards RhB oxidation, with the elimination percentage rising from 31% to 60% after 20-min reaction for 50 mL 5 mg/L RhB and 4 g/L catalyst. As to benzene oxidation, the above NaCl-assisted catalyst manifested a giant step forward from the inertness of the unmodified sample, with 82%-86% of the ∼460 ppm inlet benzene being removed by the NaCl-LiCoO2 catalyst at 350 °C and 120 L/g/h in contrast to the 5% removal efficiency of the pristine sample. Characterization studies confirmed the fully developed mesoporous structure after NaCl removal, which facilitated the reactant diffusion as well as the accessibility of the catalytical sites, and the strengthened oxidativity of the NaCl-modified sample was ensured by its large number of surface adsorbed oxygen species. Besides, the C6H6-TPSR measurements gave a direct experimental evidence to the high activity of the oxygen species induced by NaCl modification. These favorable factors were all conducive to dye and VOCs oxidation.