A study of microwave-enhanced catalytic degradation of benzene using Co-Mn metal oxides combined with numerical simulation.

• Microwave enhanced catalytic degradation of VOCs. • High electric field distribution exists on the surface of particles. • VOCs molecule activated on the catalyst surface under microwave E-field. • The surface electronic structure was changed under microwave E-field. Microwave can enhance catalytic reaction and is a promising alternative to convention heating. Herein, microwave-enhanced catalytic degradation of benzene was investigated using Co-Mn metal oxides. Numerical calculation was employed to analyze the microwave-enhanced catalytic degradation. The catalysts were synthesized by conventional citrate sol-gel method. Then, the morphologies, elements distribution and chemical structure were characterized. Compared to conventional heating, the catalysts exhibit better activity and lower apparent activation energy under microwave heating, indicating that microwave enhance catalytic degradation of benzene. Mn1Co2 exhibits good catalytic performance under microwave heating. From the finite element simulation, it is found that the E-field distribution on the spherical particle catalyst is non-uniform, and the E-field intensity is about 1.9 × 104 V/m and 4.27 × 104 V/m at the catalyst particles and the contact position. The DFT calculation results show that the electron density of Mn-O bond decreases and the charge density of Co atom increases under E-field, which is conducive to the molecule activation and electron transfer. The density of states results demonstrate the microwave E-field leads to lower electron energy on the surface, resulting in enhanced catalytic reaction. Combined with the results of finite element calculation, the microwave enhancement effect is more pronounced at the catalyst contact point. [Display omitted] [ABSTRACT FROM AUTHOR]