Li Jianan, Li Xinyong, Yin Zhifan, Wang Xinyang, Ma Hangfan, Wang Lianzhou
State Key Laboratory of Fine Chemicals and Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science & Technology , Dalian University of Technology , Dalian 116024 , China.
ARC Centre of Excellence for Functional Nanomaterials, School of Chemical Engineering , The University of Queensland , St. Lucia , Brisbane , Queensland 4072 , Australia.
ACS Appl Mater Interfaces. 2019 Aug 14;11(32):29004-29013. doi: 10.1021/acsami.9b11836. Epub 2019 Jul 30.
Crystal facet engineering has been proved as a versatile approach in modulating the photocatalytic activity of semiconductors. However, the facet-dependent properties and underlying mechanisms of spinel ZnFeO in photocatalysis still have rarely been explored. Herein, ZnFeO nanoparticles with different {001} and {111} facets exposed were successfully synthesized via a facile hydrothermal method. Facet-dependent photocatalytic degradation performance toward gaseous toluene under visible light irradiation was observed, where truncated octahedral ZnFeO (ZFO(T)) nanoparticles with both {001} and {111} facets exposed exhibited a superior performance than the others. The formed surface facet junction between {010} and {100} facets was responsible for the improved activity by separating photogenerated e/h pairs efficiently to reduce their recombination rate. Photogenerated electrons and holes were demonstrated to be immigrated onto {001} and {111} facets, separately. Intriguingly, electron paramagnetic resonance trapping results indicated that both O and OH were abundantly present in the ZFO(T) sample under visible light irradiation as major reactive oxygen species involved in the photocatalytic degradation process. Additionally, further investigation revealed that {001} facets played a predominant role in activating photogenerated transient species HO into OH, beneficially boosting the intrinsic photocatalytic activity. This work has not only presented a promising strategy in regulating photocatalytic performance through the synergetic effect of facet junction and specific facet activation but also broadened the application of facet engineering with multiple effects simultaneously cooperating.
晶面工程已被证明是一种调节半导体光催化活性的通用方法。然而，尖晶石型ZnFeO在光催化中依赖于晶面的性质及其潜在机制仍鲜有探索。在此，通过简便的水热法成功合成了暴露不同{001}和{111}晶面的ZnFeO纳米颗粒。观察到在可见光照射下对气态甲苯的晶面依赖性光催化降解性能，其中同时暴露{001}和{111}晶面的截顶八面体ZnFeO（ZFO(T)）纳米颗粒表现出比其他颗粒更优异的性能。{010}和{100}晶面之间形成的表面晶面结通过有效分离光生电子/空穴对以降低其复合率，从而提高了活性。光生电子和空穴分别被证明迁移到{001}和{111}晶面上。有趣的是，电子顺磁共振捕获结果表明，在可见光照射下，O和OH在ZFO(T)样品中大量存在，是参与光催化降解过程的主要活性氧物种。此外，进一步研究表明，{001}晶面在将光生瞬态物种HO活化为OH方面起主要作用，有利于提高本征光催化活性。这项工作不仅通过晶面结和特定晶面活化的协同效应提出了一种调节光催化性能的有前景的策略，而且拓宽了多种效应同时协同作用的晶面工程的应用。
