Construction of Pd/Mn3O4 heterojunction catalyst for efficient photothermal synergetic catalytic propane total oxidation

Abstract

Photothermal synergistic low-temperature catalytic volatile organic compounds (VOCs) degradation has an advantage on energy efficiency and reduction of carbon emissions. Herein, an impregnation-pyrolysis-oxidation strategy was adopted to synthesize Pd/Mn3O4 heterojunction catalyst. Under photothermal synergistic conditions, 0.60Pd/Mn3O4 catalyst exhibited an excellent activity for propane total oxidation, with a T90 value of 219.1 ℃, which was 115.3 ℃ lower than that of Mn3O4. Enhancement effect of the heterojunction structure on photothermal synergy was detected by various characterization techniques and density functional theory calculation. The presence of Pd species enhanced the low-temperature reducibility of Mn3O4. Meanwhile, O2 molecules were more easily activated at the Pd sites and overflow to the surface of Mn3O4 for reaction. Besides, the formation of p-n junction between Pd species and Mn3O4 in heterojunction structure promoted the charge separation and the migration of carriers, and boosted the generation of oxygen free radical, resulting in a significant improvement in photothermal catalytic activity. Overall, this study provided new strategy and deep insight for constructing heterojunction to enhance photothermal catalytic performance of VOC elimination.