泡沫镍网负载TiO2/WO3薄膜对乙烯的光催化降解

乙烯是果蔬采摘后腐烂变质的主要因素,如何减少或去除果蔬贮藏过程中释放的乙烯,是果蔬保鲜领域亟待解决的问题。本工作采用溶胶-凝胶法制备了一系列金属泡沫镍网负载TiO2/WO3薄膜催化剂,采用不同手段对样品进行表征分析,并以此薄膜为催化剂,考察紫外光下乙烯催化降解性能。结果表明:TiO2/WO3成功负载在泡沫镍网表面。TiO2与WO3复合后形成了异质结,抑制了电子-空穴对的复合,样品的禁带宽度减小,吸光度增强,光催化性能提升。TiO2/WO3在紫外光下展现出良好的光催化活性和光催化稳定性,当WO3占TiO2质量百分数为6%时,光催化活性最高,光催化乙烯速率常数为0.0332 min^-1,是TiO2的9.48倍,但是过量的WO3会成为电子-空穴的复合中心,降低光催化活性。研究还对紫外光下泡沫镍网负载TiO2/WO3薄膜的光催化降解乙烯机理进行了探讨。

Synthesis of TiO2/WO3 on Nickel Foam for the Photocatalytic Degradation of Ethylene

Ethylene is the main factor of postharvest spoilage of fruits and vegetables. Therefore, how to reduce or remove the ethylene released during the storage of fruits and vegetables is a problem to be solved. In this study, a series of nickel foam supported TiO₂/WO₃ were prepared by Sol-Gel method. The samples were characterized by different methods. The photocatalytic degradation activity of ethylene under ultraviolet light irradiation was investigated. The results show that TiO₂/WO₃ film is successfully supported on the nickel foam, and there formed heterojunction between TiO₂ and WO₃, which efficiently enhanced the separation and transfer rates of photogenerated electron and hole. The narrowed band-gap also leads to a red shift of optical absorbance and high photoactivity. The photocatalytic activity and stability of TiO₂/WO₃ were excellent under UV light irradiation. When the mass percentage of WO₃ is 6% of TiO₂, the photocatalytic ethylene degradation of the TiO₂/WO₃ composite film reaches maximum, and the degradation rate constant is almost 9.8 times as that of TiO₂. The mechanism of photocatalytic degradation of ethylene by TiO₂/WO₃ supported on nickel foam under ultraviolet light irradiation was also discussed.