Revealing the enhanced photocatalytic properties of ZnO tetrapods produced by atmospheric-pressure microwave plasma jet system

Abstract

We demonstrated the synthesis of ZnO tetrapod using an atmospheric pressure microwave plasma (APMP) jet system and evaluated its photocatalytic properties in terms of the size, specific surface area, crystal facet, and chemical state of the surface. The APMP was ignited using oxygen and nitrogen gases and ZnO tetrapods were produced from a microsized Zn powder. The average size increased with an increase in plasma power. At the same applied plasma power, the average size increased far away from the plasma plume. The photocatalytic performance was evaluated based on the decomposition of methylene blue (MB) solution under UV light irradiation. We found that the chemical state of the surface is more critical in determining the photocatalytic performance rather than surface area and crystal facet dependence. The result is attributed to the modified ZnO tetrapod surface during the high energetic APMP process, which makes the UV interactive.