Solution combustion synthesis of Co oxide-based catalysts for phenol degradation in aqueous solution

Solution combustion using urea as a fuel was employed to synthesise Co oxide and Al2O3-, SiO2- and TiO2-supported Co oxide catalysts. The catalysts were characterised using several techniques such as N2 adsorption/desorption, XRD, FTIR, UV–vis diffuse reflectance and SEM–EDX, and their catalytic activity was evaluated in phenol degradation in aqueous solution with sulphate radicals. Solution combustion is a simple and effective method in preparation of supported Co catalysts. Co3O4 was the major Co crystal phase in the samples prepared via the combustion synthesis. Bulk Co3O4 particles were not effective in reaction, but supported Co oxides showed higher activity than unsupported Co oxide. The supports influenced Co dispersion and catalytic activity. Co/TiO2 exhibited the highest activity, but it deactivated much faster than other two supported catalysts. Co/SiO2 showed a comparable activity to Co/Al2O3 and the best stability among the three Al2O3-, SiO2- and TiO2-supported Co catalysts.

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► One-step solution combustion was firstly employed to prepare supported Co oxide catalysts.
► Co/SiO2 exhibited high and stable performance in phenol degradation.
► Metal oxide dispersion and support surface basicity are important factors influencing catalytic performance.