Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment , Chinese Academy of Sciences , Xi'an 710061 , China.
ACS Appl Mater Interfaces. 2019 Mar 13;11(10):10042-10051. doi: 10.1021/acsami.9b00111. Epub 2019 Feb 27.
Previous research has evidenced the insufficient efficiency in a one-step modified photocatalyst for NO removal. In this article, a serial multistep modification was explored to improve the NO removal activity of g-CN. In the experiment, a g-CN photocatalyst has been successfully modified by Cu elements three times on one continuous process. Meanwhile, results showed that the serial multistep modifications could improve NO removal activity by g-CN step by step. The main active species in the g-CN system were h and O but they were h and OH in the three-modified g-CN systems. Moreover, different mechanisms of activity improvement caused by the modified Cu in the serial-modified samples were identified. In the first modified sample, Cu can decompose HO molecules into OH via a Fenton-like reaction. In the second modified sample, the HO molecule is activated by Cu and decomposed into OH by the generated photoelectrons. After the third modification, the synergistic effects of the N vacancy and Cu were identified, which significantly enhanced the photocatalytic NO removal activity of g-CN. This study proposed that the serial multistep modification can be a promising method to improve the NO removal activity of g-CN stage-by-stage.
先前的研究表明，一步法改性光催化剂在去除 NO 方面的效率不够高。本文探索了一种连续的多步改性方法，以提高 g-CN 的 NO 去除活性。在实验中，通过连续的一个过程，成功地将 g-CN 光催化剂三次用 Cu 元素进行了改性。同时，结果表明，连续多步改性可以逐步提高 g-CN 的 NO 去除活性。g-CN 体系中的主要活性物质是 h 和 O，但在三改性 g-CN 体系中则是 h 和 OH。此外，还确定了由连续改性样品中改性 Cu 引起的活性提高的不同机制。在第一个改性样品中，Cu 可以通过类芬顿反应将 HO 分子分解为 OH。在第二个改性样品中，HO 分子被 Cu 激活，并通过产生的光电子分解为 OH。经过第三次改性，鉴定出 N 空位和 Cu 的协同作用，显著提高了 g-CN 的光催化 NO 去除活性。本研究提出，连续多步改性可以是一种很有前途的方法，能够逐步提高 g-CN 的 NO 去除活性。
