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Herein we demonstrate that the performance of mesoporous silica SBA-15 and SBA-15-Ag impregnated during plasma ammonia synthesis depend on the plasma conditions. At high power the mesoporous silica SBA-15 without Ag produces the largest amount of ammonia observed in our experiments, but the addition of Ag provides a minor benefit at lower powers. Plasma conditions were analyzed using optical emission spectroscopy using N2, N2+ and NH molecular bands and H{\alpha} lines. The analysis of optical emission, specifically Ha lines and N2 molecular bands data shows that SBA-15 has higher electron density, and higher N2 vibrational temperature. Stronger N2+ emission relative to the neutral N2 provides additional evidence for higher electron density in the SBA-15 packed bed reactors. The addition of Ag resulted in a lower concentration of atomic hydrogen. Where Ag acts as a hydrogen sink facilitating surface reactions with nitrogen. The presence NH in the spectrum may indicate a higher concentration of H in the SBA-15 reactor. From the materials point of view SBA-15 is a more robust catalyst with a commendable surface area retention after plasma exposure due to the lack of local heating generated when a metal is in the structure., Comment: 43 Pages, 13 figures

There is an urgent need for disinfection and sterilization devices accessible to the public that can be fulfilled by innovative strategies for using cold atmospheric pressure plasmas. Here we explore and evaluate an approach combining a flexible printed circuit design of a dielectric barrier discharge (DBD) with an environmentally safe chemical reagent for surface decontamination from bacterial contaminants. The device operates in ambient air without any additional gas flow at a power density of about 0.5 W/cm^2. Using a 3% hydrogen peroxide solution as a model reagent we demonstrate improved reduction in the bacterial load of a surface contaminant of >6log10 in 90 seconds, about 3log10 and 2log10 faster compared to hydrogen peroxide alone and the flexible DBD alone, respectively, for the same treatment time. The synergistic action of the plasma bioactive properties and hydrogen peroxide result in a dramatic improvement of surface disinfection. This opens new possibilities for using the low power flexible DBD plasma sources for surface disinfection and decontamination., Comment: 16 pages, 4 figures