Abstract: The solubility of ammonium tungstate in a special hydrothermal condition is exploited to synthesize uniform microspheres of Ce-Cu-W-O oxides. Compared to their W-undoped counterparts, they possess more Ce³⁺ and oxygen vacancies, thereby promoting oxygen mobility. The formed rich WO₃ surface can effectively provide acid sites, which is helpful for adsorption of vinyl chloride and interrupting the C-Cl bond. In addition, the presence of WO₃ induces the formation of finer CuO nanoparticles with respect to the traditional coprecipitation method, thereby resulting in a better reducibility. Benefiting from both the enhanced acidity and reducibility, the Ce-Cu-W-O microspheres deliver excellent low-temperature vinyl chloride oxidation activity (a reaction rate of 2.01×10^-7 mol/(g_cat·s) at 250 ℃) and high HCl selectivity. Moreover, subtle deactivation occurs after the three cycling activity tests, and a stable vinyl chloride conversion as well as mineralization are observed during the 72-h durability test at 300 ℃, which demonstrates good thermal stability. Our strategy can provide new insights into the design and synthesis of metal oxides for catalytic oxidation of chlorinated volatile organic compounds.

Key words: Catalytic vinyl chloride oxidation, Ce-Cu-W-Omicrospheres, Solubility of ammonium tungstate, Rich surface WO₃, Fine CuO nanoparticles