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Indexed by:期刊论文

Date of Publication:2016-01-27

Journal:ACS APPLIED MATERIALS & INTERFACES

Included Journals:SCIE、EI、PubMed

Volume:8

Issue:3

Page Number:2111-2119

ISSN No.:1944-8244

Key Words:Z-scheme; electron mediator; Fermi level; charge transfer; photocatalysis

Abstract:Z-scheme photocatalytic system shows superiority in degradation of refractory pollutants and water splitting due to the high redox capacities caused by its unique charge transfer behaviors. As a key component of Z-scheme system, the electron mediator plays an important role in charge carrier migration. According to the energy band theory, we believe the interfacial energy band bendings facilitate the electron transfer via Z-scheme mechanism when the Fermi level of electron mediator is between the Fermi levels of Photosystem II (PS II) and Photosystem I (PS I), whereas charge transfer is inhibited in other cases as energy band barriers would form at the semiconductor-metal interfaces. Here, this inference was verified by the increased hydroxyl radical generation and improved photocurrent on WO3-Cu-gC(3)N(4) (with the desired Fermi level structure), which were not observed on either WO3-Ag-gC(3)N(4) or WO3-Cu-gC(3)N(4). Finally, photocatalytic degradation rate of 4-nonylphenoI on WO3-Cu-gC(3)N(4) was proved to be as high as 11.6 times than that of WO3-gC(3)N(4), further demonstrating the necessity of a suitable electron mediator in Z-scheme system. This study provides scientific basis for rational construction of Z-scheme photocatalytic system.