Zhu Lejie, Luo Jianmin, Dong Guohui, Lu Yun, Lai Yinlong, Liu Jun, Chen Guanmei, Zhang Yi
College of Chemistry and Civil Engineering, Shaoguan University Shaoguan 512005 PR China
School of Environmental Science and Engineering, Shanxi University of Science and Technology Xi'an 710021 PR China
RSC Adv. 2021 Oct 12;11(53):33373-33379. doi: 10.1039/d1ra05329a. eCollection 2021 Oct 8.
As a kind of metal-free organic semiconductor photocatalyst, g-CN has been widely explored for use in photocatalysis. However, the low quantum yield, small absorption range, and poor conductivity limit its large-scale application. Introducing another kind of semiconductor, particularly an oxide semiconductor, can result in some unexpected properties, such as an improved change transfer, enhanced light absorption, and better conductivity. In this work, CuO/g-CN is successfully prepared through an impregnation and post-calcination method. A series of measurements support the formation of an organic-inorganic hybrid p-n heterojunction at the CuO (p-type) and g-CN (n-type) interface. Furthermore, the photoactivity of the composite is evaluated photocatalytic NO removal and the visible degradation of rhodamine B (RhB). Results show that the photocatalytic properties of CuO/g-CN are almost twice as high as those of g-CN. In comparative tests, the photocatalytic degradation performance of Mix-CuO/g-CN (the mixture of CuO and g-CN nanosheets prepared by mechanically mixing) is even lower than that of pure g-CN. The degradation of RhB is only 19.7% under visible light after 30 min of irradiation. The improvement in the photoactivity of CuO/g-CN results from the built-in electric field close to the formed p-n heterojunction, which switches the electron transfer mechanism from a double-charge transfer mechanism to a Z-scheme mechanism. In addition, the formed p-n heterojunction favors charge transfer, and thus the photocatalytic performance is significantly improved.
作为一种无金属有机半导体光催化剂，石墨相氮化碳（g-CN）已被广泛研究用于光催化领域。然而，其低量子产率、小吸收范围和差的导电性限制了它的大规模应用。引入另一种半导体，特别是氧化物半导体，可能会产生一些意想不到的特性，如改善电荷转移、增强光吸收和更好的导电性。在这项工作中，通过浸渍和后煅烧方法成功制备了氧化铜（CuO）/石墨相氮化碳（g-CN）。一系列测量结果支持了在CuO（p型）和g-CN（n型）界面处形成有机-无机杂化p-n异质结。此外，通过光催化去除一氧化氮（NO）和可见光下降解罗丹明B（RhB）来评估该复合材料的光活性。结果表明，CuO/g-CN的光催化性能几乎是g-CN的两倍。在对比试验中，机械混合制备的混合CuO/g-CN（CuO和g-CN纳米片的混合物）的光催化降解性能甚至低于纯g-CN。光照30分钟后，可见光下RhB的降解率仅为19.7%。CuO/g-CN光活性的提高源于靠近形成的p-n异质结的内建电场，它将电子转移机制从双电荷转移机制转变为Z型机制。此外，形成的p-n异质结有利于电荷转移，因此光催化性能得到显著提高。
