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/Mn 3 O 4 heterojunction catalyst. Under photothermal synergistic conditions, 0.60Pd/Mn 3 O 4 catalyst exhibited an excellent activity for propane total oxidation, with a T 90 value of 219.1 ℃, which was 115.3 ℃ lower than that of Mn 3 O 4 . 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 Mn 3 O 4 . Meanwhile, O 2 molecules were more easily activated at the Pd sites and overflow to the surface of Mn 3 O 4 for reaction. Besides, the formation of p-n junction between Pd species and Mn 3 O 4 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.
Adjusting the interaction between dual active components for enhancing volatile organic compounds (VOCs) degradation is an effective but still challenging means of air pollution control. Herein, a limited pyrolysis oxidation strategy was adopted to prepare Pd-Mn 3 O 4 spinel catalysts with uniform morphology and active component dispersion. Among these, 1.08Pd-Mn 3 O 4 presented the highest catalytic efficiency with a T 90 value of 240 °C, which was 94 °C lower than that of Mn 3 O 4 . Characterization and density functional theory (DFT) calculation results revealed that the strong metal-support interaction (SMSI) effect between Pd and Mn 3 O 4 promoted the redistribution of surface charges, thus strengthening the oxidation-reduction ability of the active sites. Moreover, the SMSI effect led to a better migration of surface oxygen species, and boosted the generation of active surface oxygen species. Simultaneously, the Pd catalyst further reduced the energy barrier in the initial stage of the dehydrogenation of propane. Overall, this study provided a novel design strategy for dual active components catalysts with SMSI effect and extended the application of these catalysts in the important field of VOCs elimination.
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