Electric field promoted oxidation of naphthalene over Cu/Ce0.55Zr0.45O catalysts at low temperature

Electric field was applied into the catalytic oxidation for the naphthalene over m% Cu/Ce0.55Zr0.45O2 catalysts. It was found that catalysts with 2% Cu loading exhibit the best catalytic performance and complete naphthalene conversion was achieved at low temperature of 150 °C. The effect of Cu modification and electric field were thoroughly investigated with various characterization technologies. It was found that the doping of Cu to Ce0.55Zr0.45O2 support is beneficial for the oxygen availability and regeneration capability, but suppressive for the naphthalene adsorption. Without electric field, the oxygen availability is the rate determining factor since the oxidation of adsorbed naphthalene on the catalyst surface is the lowest compared with the adsorption and oxygen regeneration process. Under the electric field, the conduction of electricity is through the occupation and reformation of oxygen vacancies by O ion, leading to highly improved oxygen mobility in the catalyst lattice. In addition, the formed Ce3+ in the electric field can easily be re-oxidized by the adjacent CuO, making oxygen species in CuO available for the naphthalene oxidation. Thus the catalytic performance was promoted due to the improved oxygen availability in the electric field and the optimized Cu loading is a balance between the adsorption ability and regeneration capability.