Constructing nitrogen vacancy introduced g-C3N4 p-n homojunction for enhanced photocatalytic activity
Constructing nitrogen vacancy introduced g-C3N4 p-n homojunction for enhanced photocatalytic activity
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构建氮空位引入g-C3N4 p-n同质结以增强光催化活性
DOI：
10.1016/j.jece.2019.102984
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发表时间：
2019-04-01
影响因子：
7.7
通讯作者：
Tang, Heqing
中科院分区：
文献类型：
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作者：
Cao, Jin;Pan, Cong;Tang, Heqing
p-n同质结是光催化剂的一种有效结构，可以改善光生载流子的分离，最终提高其光催化活性。在目前的工作中，通过在氢气气氛下二次煅烧块状g-C3N4，将氮空位（NVs）引入n型石墨碳氮化物（g-C3N4）中，以构建g-C3N4 p-n同质结。通过一系列表征证实g-C3N4中形成了NVs，并且随着二次焙烧时间的延长，NVs的数量逐渐增加。此外，“V形”莫特-肖特基图确定结构的导电类型为p-n型。光电化学测量结果表明p-n同质结比g-C3N4更有效地分离和转移光生载流子。因此，p-n同质结g-C3N4的光催化活性显着增强。 p-n同质结g-C3N4对罗丹明b的降解率约为本体g-C3N4的8.3倍。所构建的p-n同质结体系中反应自由基的种类和数量显着增加。通过将NVs引入g-C3N4中成功合成p-n同质结可能是净化含有机污染物的废水的有用技术。
p-n homojunction is an efficient structure for a photocatalyst to improve separation of photo-generated carriers, and finally promote its photocatalytic activity. In the present work, the nitrogen vacancies (NVs) have been introduced to the n-type graphitic carbon nitride (g-C3N4) via secondary calcination of bulk g-C3N4 under hydrogen atmosphere for the construction of g-C3N4 p-n homojunction. The NVs were confirmed to be formed in g-C3N4 by a series of characterizations, and the amount of NVs gradually increased with the extension of secondary calcination time. Furthermore, the "V-shaped" Mott-Schottky plots determined the conductivity type of construction was p-n type. The results of photoelectrochemical measurement demonstrate p-n homojunction separated and transferred photo-generated carriers much more efficiently than by-type g-C3N4. Therefore, significantly enhanced photocatalytic activity was obtained for p-n homojunctions g-C3N4. The degradation rate for rhodamine b by p-n homojunction g-C3N4 was about 8.3 times that by bulk g-C3N4. The variety and quantity of reactive radicals were significantly increased in the constructed p-n homojunction system. The successful synthesis of p-n homojunction by introducing NVs into g-C3N4 may be a useful technique for purifying wastewater containing organic pollutants.