Probing the Nature of Bandgap States in Hydrogen-Treated TiO2 Nanowires

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Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, United States
Department of Chemistry, University of California, Riverside, 501 Big Springs Road, Riverside, California 92521 United States
§ NanoBio Interface Group, Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
*E-mail [email protected], Ph (831)-459-1952 (Y.L.).
*E-mail [email protected], Ph (831) 459-3776 (Z.Z.).
Cite this: J. Phys. Chem. C 2013, 117, 50, 26821–26830
Publication Date (Web):December 2, 2013
Copyright © 2013 American Chemical Society
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Hydrogen treatment of TiO2 has been demonstrated to significantly alter its optical properties, including substantially enhanced visible light absorption that has important implications for various applications. The chemical nature of the bandgap states responsible for the increased visible absorption is not yet well understood. This work reports a detailed study of the structural, optical, electronic, and ultrafast properties of hydrogen-treated TiO2 (H:TiO2) nanowires (NWs) using a combination of experimental techniques including high-resolution transmission electron microscopy (HRTEM), electron spin resonance spectroscopy (ESR), time-resolved fluorescence (TRF), and femtosecond transient absorption (TA) spectroscopy in order to explain the origin of the strong visible absorption. The combined TEM, ESR, TRF, and TA data suggest that the presence of a localized mid-bandgap oxygen vacancy (VO) occupied by a lone electron in an antibonding orbital situated at a surface site is likely responsible for the visible absorption of the material. The data further indicate that while untreated TiO2 NWs are fluorescent, the hydrogen treatment leads to quenching of the fluorescence and highly efficient charge carrier recombination from the VO state following excitation with visible light. With UV excitation, however, the charge carrier recombination of the H:TiO2 NWs exhibits a larger component of a slow decay compared to that of untreated TiO2, which is correlated with enhanced photoelectrochemical performance. Both the treated and untreated samples exhibit a fast decay that dominates the TA signals, which is likely caused by a high density of surface trap states. A simple model is proposed to explain all the key optical and dynamic features observed. The results have provided deeper insight into the chemical nature and photophysical properties of bandgap states in chemically modified TiO2 nanomaterials.

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  2. Hee Min Hwang, Simgeon Oh, Jae-Hyun Shim, Young-Min Kim, Ansoon Kim, Doyoung Kim, Joosung Kim, Sora Bak, Yunhee Cho, Viet Q. Bui, Thi Anh Le, Hyoyoung Lee. Phase-Selective Disordered Anatase/Ordered Rutile Interface System for Visible-Light-Driven, Metal-Free CO2 Reduction. ACS Applied Materials & Interfaces 2019, 11 (39) , 35693-35701.
  3. Ossama Elbanna, Mamoru Fujitsuka, Sooyeon Kim, Tetsuro Majima. Charge Carrier Dynamics in TiO2 Mesocrystals with Oxygen Vacancies for Photocatalytic Hydrogen Generation under Solar Light Irradiation. The Journal of Physical Chemistry C 2018, 122 (27) , 15163-15170.
  4. Jennifer L. Peper, David J. Vinyard, Gary W. Brudvig, and James M. Mayer . Slow Equilibration between Spectroscopically Distinct Trap States in Reduced TiO2 Nanoparticles. Journal of the American Chemical Society 2017, 139 (8) , 2868-2871.
  5. Yesheng Li, Zilong Tang, Junying Zhang, and Zhongtai Zhang . Defect Engineering of Air-Treated WO3 and Its Enhanced Visible-Light-Driven Photocatalytic and Electrochemical Performance. The Journal of Physical Chemistry C 2016, 120 (18) , 9750-9763.
  6. Riley E. Rex, Yi Yang, Fritz J. Knorr, Jin Z. Zhang, Yat Li, and Jeanne L. McHale . Spectroelectrochemical Photoluminescence of Trap States in H-Treated Rutile TiO2 Nanowires: Implications for Photooxidation of Water. The Journal of Physical Chemistry C 2016, 120 (6) , 3530-3541.
  7. James J. Brancho and Bart M. Bartlett . Challenges in Co-Alloyed Titanium Oxynitrides, a Promising Class of Photochemically Active Materials. Chemistry of Materials 2015, 27 (21) , 7207-7217.
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  10. Haining Chen, Zhanhua Wei, Keyou Yan, Yang Bai, and Shihe Yang . Unveiling Two Electron-Transport Modes in Oxygen-Deficient TiO2 Nanowires and Their Influence on Photoelectrochemical Operation. The Journal of Physical Chemistry Letters 2014, 5 (16) , 2890-2896.
  11. Reza Montahaei, S.A. Seyyed Ebrahimi, Amin Yourdkhani, Reza Poursalehi. Photoelectrochemical properties of butane flame-treated niobium-doped hematite thin films grown by the liquid-phase deposition method. Journal of Alloys and Compounds 2022, 894 , 162428.
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  13. Rahul B. Pujari, Dong-Weon Lee. Oxygen-Deficient Metal Oxide Nanostructures for Photocatalytic Activities. 2021,,, 329-353.
  14. Nikita Denisov, Shanshan Qin, Gihoon Cha, JeongEun Yoo, Patrik Schmuki. Photoelectrochemical properties of “increasingly dark” TiO2 nanotube arrays. Journal of Electroanalytical Chemistry 2020, 872 , 114098.
  15. Yanmei Huang, Yu Yu, Yifu Yu, Bin Zhang. Oxygen Vacancy Engineering in Photocatalysis. Solar RRL 2020, 4 (8) , 2000037.
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  17. T.S. Rajaraman, Sachin P. Parikh, Vimal G. Gandhi. Black TiO2: A review of its properties and conflicting trends. Chemical Engineering Journal 2020, 389 , 123918.
  18. Qiang Wu, Bin Wang, Zhongqing Liu. Tailoring eletronic structure of Pd nanoparticles via MnO2 as electron transfer intermediate for enhanced hydrogen evolution reaction. Chemical Physics Letters 2020, 748 , 137405.
  19. Yan Liu, Ping Chen, Yaqi Fan, Yanfei Fan, Xifeng Shi, Guanwei Cui, Bo Tang. Grey Rutile TiO2 with Long-Term Photocatalytic Activity Synthesized Via Two-Step Calcination. Nanomaterials 2020, 10 (5) , 920.
  20. Xingchen Fu, Hui Chang, Zhichao Shang, Pingle Liu, Jikai Liu, He'an Luo. Three-dimensional Cu2O nanorods modified by hydrogen treated Ti3C2TX MXene with enriched oxygen vacancies as a photocathode and a tandem cell for unassisted solar water splitting. Chemical Engineering Journal 2020, 381 , 122001.
  21. Xianyin Song, Dong He, Wenqing Li, Zunjian Ke, Jiangchao Liu, Chongyang Tang, Li Cheng, Changzhong Jiang, Ziyu Wang, Xiangheng Xiao. Anionic Dopant Delocalization through p‐Band Modulation to Endow Metal Oxides with Enhanced Visible‐Light Photoactivity. Angewandte Chemie 2019, 131 (46) , 16813-16820.
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  32. Bin Wang, Shaohua Shen, Samuel S. Mao. Black TiO 2 for solar hydrogen conversion. Journal of Materiomics 2017, 3 (2) , 96-111.
  33. Mingce Long, Longhui Zheng. Engineering vacancies for solar photocatalytic applications. Chinese Journal of Catalysis 2017, 38 (4) , 617-624.
  34. Gongming Wang, Yi Yang, Dongdong Han, Yat Li. Oxygen defective metal oxides for energy conversion and storage. Nano Today 2017, 13 , 23-39.
  35. Jinhua Xiong, Yuhao Liu, Shijing Liang, Shiying Zhang, Yanhua Li, Ling Wu. Insights into the role of Cu in promoting photocatalytic hydrogen production over ultrathin HNb3O8 nanosheets. Journal of Catalysis 2016, 342 , 98-104.
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  38. Jiawei Xue, Xiaodi Zhu, Yi Zhang, Wendong Wang, Wei Xie, Jilong Zhou, Jun Bao, Ying Luo, Xiang Gao, Yong Wang, Ling-yun Jang, Song Sun, Chen Gao. Nature of Conduction Band Tailing in Hydrogenated Titanium Dioxide for Photocatalytic Hydrogen Evolution. ChemCatChem 2016, 8 (12) , 2010-2014.
  39. Xijian Liu, Yangang Sun, Yeying Wang, Lijuan Zhang, Jie Lu. Synthesis and photocatalytic activities of Nd-doped TiO 2 mesoporous microspheres. Functional Materials Letters 2016, 09 (01) , 1650013.
  40. Wenlong Guo, Zhiyao Duan, Oluwaniyi Mabayoje, William D. Chemelewski, Peng Xiao, Graeme Henkelman, Yunhuai Zhang, C. Buddie Mullins. Improved Charge Carrier Transport of Hydrogen-Treated Copper Tungstate: Photoelectrochemical and Computational Study. Journal of The Electrochemical Society 2016, 163 (10) , H970-H975.
  41. Licheng Li, Kangzhong Shi, Rui Tu, Qi Qian, Dong Li, Zhuhong Yang, Xiaohua Lu. Black TiO2(B)/anatase bicrystalline TiO2–x nanofibers with enhanced photocatalytic performance. Chinese Journal of Catalysis 2015, 36 (11) , 1943-1948.
  42. Wenzhi Ren, Yong Yan, Leyong Zeng, Zhenzhi Shi, An Gong, Peter Schaaf, Dong Wang, Jinshun Zhao, Baobo Zou, Hongsheng Yu, Ge Chen, Eric Michael Bratsolias Brown, Aiguo Wu. A Near Infrared Light Triggered Hydrogenated Black TiO 2 for Cancer Photothermal Therapy. Advanced Healthcare Materials 2015, 4 (10) , 1526-1536.
  43. Jing Di, Xincui Fu, Huajun Zheng, Yi Jia. H–TiO2/C/MnO2 nanocomposite materials for high-performance supercapacitors. Journal of Nanoparticle Research 2015, 17 (6)
  44. Zhong-guo Li, Lingyan Liang, Hongtao Cao, Zhengguo Xiao, Xingzhi Wu, Yu Fang, Junyi Yang, Tai-Huei Wei, Ying-lin Song. Ultrafast carrier dynamics in SnO x thin films. Applied Physics Letters 2015, 106 (10) , 102103.
  45. Xiaoying Zhang, Zhuoyuan Chen. Enhanced photoelectrochemical performance of the hierarchical micro/nano-structured TiO 2 mesoporous spheres with oxygen vacancies via hydrogenation. RSC Advances 2015, 5 (13) , 9482-9488.
  46. , , , Riley E. Rex, Fritz J. Knorr, Jeanne L. McHale. Spectroelectrochemical photoluminescence of titanium dioxide nanosheets and nanoparticles in aqueous and nonaqueous environments. 2014,,, 91650T.