Surface states as electron transfer pathway enhanced charge separation in TiO2 nanotube water splitting photoanodes

被引：91

作者：

Zhu, Heng ^{[1
]}

Zhao, Meiming ^{[1
]}

Zhou, Junkang ^{[2
]}

Li, Wenchao ^{[1
]}

Wang, Haoyu ^{[2
]}

Xu, Zhe ^{[1
]}

Lu, Lei ^{[1
]}

Pei, Lang ^{[1
]}

Shi, Zhan ^{[2
]}

Yan, Shicheng ^{[1
]}

Li, Zhaosheng ^{[1
]}

Zou, Zhigang ^{[1
,2
,3
]}

机构：

[1] Nanjing Univ, Collaborat Innovat Ctr Adv Microstruct, Coll Engn & Appl Sci, Ecomat & Renewable Energy Res Ctr ERERC, 22 Hankou Rd, Nanjing 210093, Jiangsu, Peoples R China

[2] Nanjing Univ, Dept Phys, Jiangsu Key Lab Nano Technol, Natl Lab Solid State Microstruct, 22 Hankou Rd, Nanjing 210093, Jiangsu, Peoples R China

[3] Macau Univ Sci & Technol, Macau Inst Syst Engn, Macau 999078, Peoples R China

来源：

APPLIED CATALYSIS B-ENVIRONMENTAL | 2018年 / 234卷

基金：

中国国家自然科学基金;

关键词：

Photoelectrocatalysis; TiO(2 )nanotube; Mott-Schottky (M-S); Surface states; Charge separation; INITIO MOLECULAR-DYNAMICS; CONDUCTION-BAND ELECTRONS; HEMATITE PHOTOANODE; HOLE RECOMBINATION; OXIDATION-KINETICS; ARRAYS; ANATASE; PHOTOELECTRODES; PHOTOCATALYSIS; PHOTOCURRENT;

D O I：

10.1016/j.apcatb.2018.04.040

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Surface states on TiO2 photoanodes are usually considered to hinder the photoelectrochemical (PEC) water splitting via slowing charge transport and increasing charge recombination. Here, we found that electro-chemically doping the TiO2 nanotubes electrode at a potential negative than its flat band potential will induce the insertion of protons into the lattice of TiO2 via a reaction of (TiO2)-O-IV + e(-) + H+ = (TiO)-O-III(OH) to form the surface states. Photoelectrochemical/electrochemical tests confirmed that the surface states (Ti-OH) are an important photogenerated electron transfer route, significantly increasing charge separation efficiency, and hence contributing to the PEC performance enhancement. In addition, we have made a self-consistent explanation on Mott-Schottky (M-S) plots of the TiO2 nanotubes electrode, demonstrating that the M-S measurement is able to accurately describe electron filling and extraction into/from surface states and not suitable to determine the flat band potential of nanostructured TiO2 electrodes. Our results offer a new insight to understanding the role of surface states during the charge separation, transfer, and injection processes of the water splitting reaction.

引用

页码：100 / 108

页数：9

共 73 条

[1]

Bader R. F. W., 2002, ATOMS MOL ENCY COMPU

[2] THE CONCEPT OF FERMI LEVEL PINNING AT SEMICONDUCTOR-LIQUID JUNCTIONS - CONSEQUENCES FOR ENERGY-CONVERSION EFFICIENCY AND SELECTION OF USEFUL SOLUTION REDOX COUPLES IN SOLAR DEVICES [J].