Insight into the energy band alignment of magnetically separable Ag2O/ZnFe2O4 p-n heterostructure with rapid charge transfer assisted visible light photocatalysis

By Hai Guo, Huai-Yuan Niu, Chao Liang, C. Niu, Dawei Huang, Lei Zhang, Ning Tang, Yang Yang, Chengyang Feng, Guangming Zeng. Journal of Catalysis, 2019

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Abstract The fabrication of highly efficient catalysts with easy recyclability has received great attention in the development of realistic photocatalytic applications. Herein, a magnetically separable Ag 2 O/ZnFe 2 O 4 p-n heterostructure photocatalyst was fabricated and utilized for the degradation of BPA under visible light irradiation. Results show that the obtained AZ-3 composite possesses the optimal performance, which is about 2.33-fold and 34.45-fold higher than that of Ag 2 O and ZnFe 2 O 4 , respectively. The enhanced performance is attributed to the rapid separation of photogenerated electrons and holes caused by the built-in electric field between p-type Ag 2 O and n-type ZnFe 2 O 4 , as detailedly evidenced by photoelectrochemical measurements. Moreover, density functional theory (DFT) calculations show that the electrons around the contact interface of Ag 2 O and ZnFe 2 O 4 will be redistributed after their hybridization, while the investigation on energy band alignment further indicates that a type-II band alignment with ΔE CBO  = 0.16 eV and ΔE VBO  = 0.65 eV is formed in this p-n heterostructure, which provides a solid support for the reaction mechanism. This work gives deep insights into the charge transfer properties of p-n heterostructure systems and opens new vistas for the construction of highly efficient and magnetically separable photocatalysts.

Subfields: Materials Chemistry, Renewable Energy, Sustainability and the Environment

View Paper: https://www.semanticscholar.org/paper/1a74bcda1d9f207d88412dea4f746a19dc63d533