全固态自支撑WO_(3)-CeO_(2)异质结光催化剂高效降解甲醛研究

All-solid Self-supporting WO_(3)-CeO_(2)Heterojunction Photocatalyst for Efficient Formaldehyde Degradation

针对室内空气中的挥发性有机物难以完全矿化问题,以及传统的粉体光催化剂难以实际应用问题,本研究以三维钨网为基底,一步水热法耦合煅烧制备可见光响应的窄带隙WO_(3)纳米线,再通过一步水热法制备全固态自支撑的WO_(3)-CeO_(2)异质结复合光催化剂,并将其应用于室内典型污染气体甲醛的高矿化率去除。WO_(3)独特的纳米线状结构有助于捕获空气中分散的甲醛分子;CeO_(2)与WO_(3)异质结界面形成的内建电场能有效驱动光生电子对分离,产生大量的活性自由基(•O_(2)^(−)、•OH),高效降解甲醛。在模拟太阳光的照射下,所制备的WO_(3)-CeO_(2)光催化剂能使66.96 mg/m^(3)的甲醛分子在60 min内几乎完全矿化为CO_(2)和H_(2)O。此外,由于CeO_(2)、WO_(3)的物理化学性能稳定且具有变价电对,在连续10次降解甲醛后,该光催化剂的催化活性仅降低2.1%,表现出良好的催化稳定性。该工作能够为室内除甲醛技术的发展提供科学借鉴。

In view of the difficulty of complete mineralization of volatile organic compounds in indoor air and the technical difficulties of practical application of traditional powder photocatalysts,an all-solid-state self-supporting WO_(3)-CeO_(2)heterojunction photocatalyst was prepared and applied to photocatalytic removal of a typical indoor contaminant,formaldehyde,with high mineralization rate.In WO_(3)-CeO_(2),the WO_(3)nanowire was prepared through a hydrothermal coupling with calcination method by using three dimension W net as substrate,and the CeO_(2)was further precipitated on it by hydrothermal method.The unique WO_(3)nanowire-like structure helps capture formaldehyde dispersed in the air.The internal electric field formed at the interface of CeO_(2)and WO_(3)heterojunction can effectively drive the separation of photogenerated electron pairs,and produce a large number of active free radicals(•O_(2)^(-),•OH)to degrade formaldehyde efficiently.Under the irradiation of simulated sunlight,the prepared WO_(3)-CeO_(2)photocatalyst can make 66.96 mg/m^(3)formaldehyde almost completely mineralized into CO_(2)and H_(2)O within 60 min.In addition,due to the stable physical and chemical properties and the variable valence electric pair of CeO_(2)and WO_(3),the catalytic activity of the photocatalyst decreased only 2.1%after 10 consecutive degradation of formaldehyde,showing good catalytic stability.This work will provide scientific reference for the development of indoor formaldehyde removal technology.entific reference for the development of indoor formaldehyde removal technology.