Highly photocatalytic activity of porous skeleton structure AlON powder synthesized by CRN under ultraviolet-light irradiation

Abstract

A large-sized (∼20 μm) pure aluminum oxynitride (AlON) powder characterized by its porous skeleton structure was synthesized by carbothermal reduction and nitridation (CRN) method using α-Al2O3. The photocatalytic performance of the obtained AlON powder was studied under ultraviolet-light in methylene blue (MB) solution. In 40 ml MB solution doped with 30 mg as-synthesized AlON powder, a photogradation efficiency as high as 97% was measured after irradiating 120 min, and 80% MB was mineralized by determining the total organic carbon (TOC) in the solution, i.e., mineralization is the main degradation mode of MB in the solution due to the added AlON powder. Further radical scavenger’s experiments reveal that both h+ and OH were the dominant reactive species in the photogradation process of MB by the AlON powder. It should be pointed out that the specific surface area of the obtained AlON powder is smaller than that of solid small-sized powder (∼800 nm) due to its porous skeleton structure. However, the measured photogradation efficiency of the obtained AlON powder is slightly higher than the reported value, which is mainly attributed to light reflection and scattering within its skeleton. The as-synthesized AlON powder has excellent dispersibility for its large particle size. Moreover, the obtained AlON powder also exhibits high reusability. Therefore, the obtained large-sized porous skeleton structure pure AlON powder is an efficient and promising photocatalyst.