Bi4NbO8Cl {001} nanosheets coupled with g-C3N4 as 2D/2D heterojunction for photocatalytic degradation and CO2 reduction

• Published in: Journal of hazardous materials Vol. 381; p. 121159
• Main Authors: Xu, Yue, You, Yong, Huang, Hongwei, Guo, Yuxi, Zhang, Yihe
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.01.2020
• Subjects: Bi4NbO8Cl nanosheets; bisphenol A; carbon dioxide; carbon monoxide; carbon nitride; CO2 reduction; energy; g-C3N4 heterojunction; manganese oxides; nanosheets; photocatalysis; photocatalysts; Photodegradation; synergism; tetracycline; Photodegradation; CO2 reduction; g-C3N4 heterojunction; Bi4NbO8Cl nanosheets
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2019.121159

[Display omitted] •Bi4NbO8Cl nanosheets were prepared by a molten-salt growth method.•Bi4NbO8Cl/g-C3N4 heterojunction was fabricated by ball-milling and sintering method.•Bi4NbO8Cl/g-C3N4 is demonstrated to be a type-II heterojunction.•Bi4NbO8Cl/g-C3N4 shows much enhanced photodegradation and CO2 reduction activity. Photocatalytic activity is largely restricted by insufficient photoabsorption and intense recombination between charge carriers. Here, we first synthesized Bi4NbO8Cl nanosheets with {001} exposing facets by a molten-salt growth method, which shows largely promoted photocatalytic performance for the degradation of tetracycline (TC) and bisphenol A (BPA) in comparison with Bi4NbO8Cl particles obtained by solid-state reaction. The 2D/2D Bi4NbO8Cl/g-C3N4 heterojunction photocatalysts were then fabricated via high-energy ball-milling and post-sintering to realize intimate interfacial interaction. The photocatalytic activity of all the Bi4NbO8Cl/g-C3N4 composites largely enhances compared to Bi4NbO8Cl nanosheets and g-C3N4, also far exceeding the mechanically-mixed Bi4NbO8Cl nanosheets and g-C3N4. The impact of different reaction parameters on the photocatalytic degradation activities was investigated, including catalyst concentration, pH value and TC concentration. In addition, Bi4NbO8Cl/g-C3N4 also presents improved photocatalytic CO2 reduction activity for CO production. The large enhancement on photocatalytic activity of Bi4NbO8Cl/g-C3N4 composites is owing to the synergistic effect of favorable 2D/2D structure and construction of type II heterojunction with intimate interfacial interaction, thus boosting the charge separation. The formation of type II heterojunction was evidenced by selective photo-deposition of Pt and MnOx, which demonstrate that the reductive sites and oxidative sites are on Bi4NbO8Cl nanosheets and g-C3N4, respectively. This work may provide some insights into fabrication of efficient visible-light driven photocatalysts for environmental and energy applications.