Catalytically-etched hexagonal boron nitride flakes and their surface activity

Publication date: 30 April 2017
Source:Applied Surface Science, Volume 402
Author(s): Do-Hyun Kim, Minwoo Lee, Bora Ye, Ho-Kyun Jang, Gyu Tae Kim, Dong-Jin Lee, Eok-Soo Kim, Hong Dae Kim
Hexagonal boron nitride (h-BN) is a ceramic compound which is thermally stable up to 1000°C in air. Due to this, it is a very challenging task to etch h-BN under air atmosphere at low temperature. In this study, we report that h-BN flakes can be easily etched by oxidation at 350°C under air atmosphere in the presence of transition metal (TM) oxide. After selecting Co, Cu, and Zn elements as TM precursors, we simply oxidized h-BN sheets impregnated with the TM precursors at 350°C in air. As a result, microscopic analysis revealed that an etched structure was created on the surface of h-BN flakes regardless of catalyst type. And, X-ray diffraction patterns indicated that the air oxidation led to the formation of Co3O4, CuO, and ZnO from each precursor. Thermogravimetric analysis showed a gradual weight loss in the temperature range where the weight of h-BN flakes increased by air oxidation. As a result of etching, pore volume and pore area of h-BN flakes were increased after catalytic oxidation in all cases. In addition, the surface of h-BN flakes became highly active when the h-BN samples were etched by Co3O4 and CuO catalysts. Based on these results, we report that h-BN flakes can be easily oxidized in the presence of a catalyst, resulting in an etched structure in the layered structure.

Graphical abstract

http://ift.tt/2j0BO1e