Constructing nitrogen vacancy introduced g-C3N4p-n homojunction for enhanced photocatalytic activity. Issue 2 (April 2019)

• Record Type: Journal Article
• Authors: Cao, Jin; Pan, Cong; Ding, Yaobin; Li, Wenjing; Lv, Kangle; Tang, Heqing
• Is Part Of: Journal of environmental chemical engineering. Volume 7:Issue 2(2019)
• Publication Date: 2019-04
• Subjects: p-n homojunction -- g-C3N4 -- Nitrogen vacancies -- Photocatalytic -- Degradation; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2019.102984
• Languages: English
• ISSNs: 2213-2929

Abstract

Graphical abstract: PN- x homojunction was fabricated by in situ introduced nitrogen vacancies into the framework of g-C3 N4 via secondary calcination of conventional g-C3 N4 with H2 flow. The enhanced photodegradation of RhB by PN- x homojunctions was found to be due to efficient separation of the photo-generated carriers, and O2 − and h + were confirmed as the main reactive species for RhB degradation in PN- x p-n homojunction photocatalytic system. Highlights: Nitrogen vacancy introduced g-C3 N4 /g-C3 N4 composite was successfully prepared. The conductivity of composite construction was determined as p-n type. The photocatalytic activity of p-n homojunction g-C3 N4 was significantly enhanced. The quantity of radicals was significantly increased in p-n homojunction. Abstract: 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-C3 N4 ) via secondary calcination of bulk g-C3 N4 under hydrogen atmosphere for the construction of g-C3 N4 p-n homojunction. The NVs were confirmed to be formed in g-C3 N4 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-C3 N4 . Therefore, significantly enhanced photocatalytic activity was obtained for p-n homojunctions g-C3 N4 . The degradation rate for rhodamine b by p-n homojunction g-C3 N4 was about 8.3 times that by bulk g-C3 N4 . 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-C3 N4 may be a useful technique for purifying waste-water containing organic pollutants.