Ethylene is a gaseous volatile organic compound (VOC) that works as a plant hormone to inhibit or promote plant growth. Ethylene released from fruits, vegetables, and flowers can accelerate aging and spoiling of plants even in refrigerators at low temperature. Consequently, the removal of trace amounts of ethylene at low temperature (ca. 0 8C) is imperative.Previously, biotechnological materials, such as soil bacteria, dry biobeds, and biofilters were applied for removal of ethylene. [1][2][3][4] However, high production costs and inefficiency in removing trace amounts of ethylene were drawbacks of these methods. Several photocatalysts have also been used, [5][6][7][8] but this resulted in limited application because of the more complicated working conditions required.Many attempts have been made by Hao et al. to develop gold catalysts supported on Co 3 O 4 for the removal of ethylene at low temperature. First, 2 wt % Au/Co 3 O 4 catalyst prepared by a deposition-precipitation method showed only 7.4 % conversion of ethylene at 20 8C from a relatively low concentration (1050 ppm). [9] A more active catalyst, 2.5 wt % Au nanoparticles supported on mesoporous Co 3 O 4 , was later prepared by a nanocasting method, but the catalytic activity was still insufficient for complete removal of trace (50 ppm) ethylene at 0 8C despite the complicated preparation method. [10] Gold nanoparticles supported on Co 3 O 4 rods recently prepared by a hydrothermal method solved the timeconsuming problem of catalyst preparation; however, the method afforded no significant improvement in catalytic activity. [11] Therefore, further catalyst screening is still necessary to find sufficiently active catalysts to remove low concentrations of ethylene.Herein, we report the catalytic performance of Pt nanoparticles supported on mesoporous silica MCM-41 for ethylene oxidation under low-temperature conditions. This study has revealed the influence of metals (Pt, Pd, Au, and Ag) and supports (MCM-41, SiO 2 , Al 2 O 3 , ZrO 2 , and TiO 2 ) on the catalytic performance. The Pt nanoparticles supported on MCM-41 exhibited the highest activity and demonstrated excellent durability in prolonged reaction time or recycle use.The conversion of 50 ppm ethylene over 1 wt % Pt/MCM-41 at 0 8C was over 99.8 %. To our knowledge, this is the highest conversion of ethylene oxidation at low temperature reported to date.All of the catalysts were prepared by using a typical wet impregnation method. Characterization of the catalysts was conducted by various physicochemical methods. The structural parameters are summarized in Table 1 and Table S1 (in the Supporting Information). The small-angle X-ray diffraction (XRD) patterns of MCM-41 and 5 wt % Pt/MCM-41 (Figure S1a) are consistent with the literature, [12] and peaks appeared at (100), (110), and (200), a characteristic of a typical two-dimensional hexagonal structure of mesopores in MCM-41. This result indicates that the mesoporous structure remains unchanged after the incorporation of Pt nanoparticles. However, n...

Ethylene is a gaseous volatile organic compound (VOC) that works as a plant hormone to inhibit or promote plant growth. Ethylene released from fruits, vegetables, and flowers can accelerate aging and spoiling of plants even in refrigerators at low temperature. Consequently, the removal of trace amounts of ethylene at low temperature (ca. 0 8C) is imperative.Previously, biotechnological materials, such as soil bacteria, dry biobeds, and biofilters were applied for removal of ethylene. [1][2][3][4] However, high production costs and inefficiency in removing trace amounts of ethylene were drawbacks of these methods. Several photocatalysts have also been used, [5][6][7][8] but this resulted in limited application because of the more complicated working conditions required.Many attempts have been made by Hao et al. to develop gold catalysts supported on Co 3 O 4 for the removal of ethylene at low temperature. First, 2 wt % Au/Co 3 O 4 catalyst prepared by a deposition-precipitation method showed only 7.4 % conversion of ethylene at 20 8C from a relatively low concentration (1050 ppm). [9] A more active catalyst, 2.5 wt % Au nanoparticles supported on mesoporous Co 3 O 4 , was later prepared by a nanocasting method, but the catalytic activity was still insufficient for complete removal of trace (50 ppm) ethylene at 0 8C despite the complicated preparation method. [10] Gold nanoparticles supported on Co 3 O 4 rods recently prepared by a hydrothermal method solved the timeconsuming problem of catalyst preparation; however, the method afforded no significant improvement in catalytic activity. [11] Therefore, further catalyst screening is still necessary to find sufficiently active catalysts to remove low concentrations of ethylene.Herein, we report the catalytic performance of Pt nanoparticles supported on mesoporous silica MCM-41 for ethylene oxidation under low-temperature conditions. This study has revealed the influence of metals (Pt, Pd, Au, and Ag) and supports (MCM-41, SiO 2 , Al 2 O 3 , ZrO 2 , and TiO 2 ) on the catalytic performance. The Pt nanoparticles supported on MCM-41 exhibited the highest activity and demonstrated excellent durability in prolonged reaction time or recycle use.The conversion of 50 ppm ethylene over 1 wt % Pt/MCM-41 at 0 8C was over 99.8 %. To our knowledge, this is the highest conversion of ethylene oxidation at low temperature reported to date.All of the catalysts were prepared by using a typical wet impregnation method. Characterization of the catalysts was conducted by various physicochemical methods. The structural parameters are summarized in Table 1 and Table S1 (in the Supporting Information). The small-angle X-ray diffraction (XRD) patterns of MCM-41 and 5 wt % Pt/MCM-41 (Figure S1a) are consistent with the literature, [12] and peaks appeared at (100), (110), and (200), a characteristic of a typical two-dimensional hexagonal structure of mesopores in MCM-41. This result indicates that the mesoporous structure remains unchanged after the incorporation of Pt nanoparticles. However, n...

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The quality of microcapsules directly determines the performance of microcapsule‐based functional materials, such as self‐healing materials. How to achieve high‐quality microcapsules depends on not only the selected microencapsulation technique but also the process regulation. Herein, using tetraethylenepentamine (TEPA) as the core target to be encapsulated by a novel microencapsulation technique through integrating microfluidic T‐junction and interfacial polymerization, this investigation studied how the process parameters influence the microencapsulation process and the quality of the synthesized microcapsules regarding the size, morphology, shell structure, and composition. The studied parameters include the solvent type and surfactant concentration in the co‐flow solution, the fed volume of the co‐flow solution, the types of the solvent, catalyst, and shell‐forming monomer in the reaction solution for the shell‐growth stage, and the reaction temperature at the shell‐growth stage. The influence mechanisms were established based on the observations, and the optimized parameter combination for the process was achieved. Through the parametric study for the microencapsulation technique, this study also lays a solid foundation for the technique to fabricate microcapsules containing other functional substances with high quality.

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