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Three porous nanosphere-structured manganese oxide (MnOx) catalysts were prepared and used for the low-temperature catalytic oxidation of methanol using different organic reagents as structure-directing agents to modulate the surface morphology of the catalysts. The structure-effect relationship between MnOx catalysts with different microsphere structures and the catalytic oxidation activity of methanol were analyzed using various characterization techniques. The MnOx–J catalyst had significantly higher catalytic oxidation activity for methanol (T90 = 130 °C) than the other MnOx catalysts. The characterization results indicate that the regulation of 2-methylimidazole promotes the formation of structural defects, surface-adsorbed oxygen, and Mn3+ on the surface of the manganese-based catalysts and enhances the low-temperature reduction capacity of the catalysts—the primary reason for the high reactivity of the MnOx–J samples. Three MnOx catalysts with porous nanosphere structures were synthesized using different organic reagents as structure-directing agents. Among them, the 2-methylimidazole organo-reagent promoted the formation of structural defects, surface adsorbed oxygen and Mn3+ on the surface of the manganese-based catalysts, thus enhancing the catalytic oxidation activity of the catalysts in low-temperature methanol-catalyzed reactions. [ABSTRACT FROM AUTHOR]

• The pure manganese oxides Mn 2 O 3 @δ-MnO 2 core-shell structures can be fine-manipulated via a novel synthesis method. • The synergistic effect of δ-MnO 2 nanosheets and Mn 2 O 3 microspheres is the key to enhance the deep methanol oxidation. • The Mn 2 O 3 @δ-MnO 2 interface structure exhibited more Mn4+, well redox ability and active surface lattice oxygen. • Activity study revealed that the Mn 2 O 3 @δ-MnO 2 -8h catalyst has excellent activity for low-temperature methanol oxidation. In order to elucidate the special role of interfacial effect over nanomaterials in the catalytic oxidation of volatile organic compounds (VOCs), a series of core-shell Mn 2 O 3 @δ-MnO 2 catalysts with different degree of oriented growth were prepared by a hydrothermal method, which were applied for methanol oxidation. Besides, the structure-activity relationship over the core-shell Mn 2 O 3 @δ-MnO 2 catalysts was further explained in details by multiple characterization techniques. It was found that the strong metal-support interaction promoted the formation of the interface between Mn 2 O 3 and δ-MnO 2 , which significantly changed the physicochemical properties and catalytic behaviours of core-shell Mn 2 O 3 @δ-MnO 2 catalysts. Among all the catalysts, the catalytic performances of these core-shell catalysts were obviously better than those of pure δ-MnO 2 nanosheets and Mn 2 O 3 microspheres, and the Mn 2 O 3 @δ-MnO 2 -8h catalyst exhibited the best outstanding activity for methanol oxidation (T 90 = 119 °C). In addition, the characterization analyses showed that the interfacial effect derived from the interaction between Mn 2 O 3 and δ-MnO 2 can increase the amount of Mn4+, and surface lattice oxygen, as well as optimize the low-temperature reduction ability, which was the crucial reason for the high activity of above core-shell Mn 2 O 3 @δ-MnO 2 catalysts. [Display omitted] [ABSTRACT FROM AUTHOR]

The metal-support interaction in Pt/MnO 2 hetero-catalysts regulates the physical and chemical properties of local environment on the surface of MnO 2 materials, which is the key to improve the catalytic activity of methanol oxidation. [Display omitted] • Pt/MnO 2 hetero-catalysts with different morphologies were synthesized. • Metal-support interaction plays a pivotal role in improving catalyst performance. • Loaded Pt nanoparticles (NPs) improve the surface local environment of MnO 2 support. • Specifically, the increase of Mn4+ and surface lattice oxygen on catalyst surface. • Morphology obviously affects the fixation and regulation of Pt NPs on the support surface. Rational use of the strong metal-support interaction (SMSI) is an important way to achieve the complete destruction of volatile organic compounds (VOCs). In order to investigate the influence of SMSI on the catalytic oxidation of VOCs, three Pt/MnO 2 hetero-catalysts, i.e., Pt/α-MnO 2 , Pt/γ-MnO 2 and Pt/δ-MnO 2 , were synthesized and then applied to the catalytic oxidation of methanol. The results showed that, compared with their corresponding pure MnO 2 , the temperatures (T90) at which 90% of methanol is converted to CO 2 for the above three synthesized catalysts were reduced by 54 °C, 67 °C and 32 °C, respectively. The Pt/α-MnO 2 catalyst has the best reducibility at lower temperature (T 90 = 91 °C). Multiple characterization analyses confirm that the interaction between Pt and MnO 2 support can increase the amount of Mn4+ and surface lattice oxygen on the catalyst surface. Thanks to the optimization of local reaction environment on the catalyst surface, Pt/MnO 2 hetero-catalysts have better low temperature reduction capacity and stronger VOC deep oxidation capacity than corresponding pure MnO 2 catalysts. [ABSTRACT FROM AUTHOR]