Hydrogen incorporation by plasma treatment gives mesoporous black TiO2 thin films with visible photoelectrochemical water oxidation activity

Syed Z. Islam; Allen Reed; Suraj Nagpure; Namal Wanninayake; James F. Browning; Joseph Strzalka; Doo Young Kim; Stephen E. Rankin

doi:10.1016/j.micromeso.2017.10.036

Hydrogen incorporation by plasma treatment gives mesoporous black TiO₂ thin films with visible photoelectrochemical water oxidation activity

Syed Z. Islam, Allen Reed, Suraj Nagpure, Namal Wanninayake, James F. Browning, Joseph Strzalka, Doo Young Kim, Stephen E. Rankin

Research output: Contribution to journal › Article › peer-review

32 Scopus citations

Abstract

Neutron reflectometry (NR) is used to investigate the role of hydrogen in the visible light absorption and enhanced photoactivity for water oxidation of mesoporous black titania thin films. The cubic mesoporous frameworks of TiO₂ thin films are prepared by a surfactant-templated sol-gel method and subsequently treated with hydrogen plasma, an approach hypothesized to capitalize on the high degree of disorder in the material and the high energy of the plasma species to achieve efficient hydrogen doping. UV-vis absorbance spectra indicate broad-spectrum visible light absorption in H₂ plasma-treated black TiO₂ films, and XPS indicates the generation of reduced Ti³⁺ in the treated films. The presence of hydrogen in black mesoporous titania (H-TiO₂) films is confirmed by the scattering length density (SLD) profiles obtained from neutron reflectometry measurements. The H-TiO₂ shows ca. 28 times and 8 times higher photocurrent for photoelectrochemical water oxidation compared to undoped TiO₂ films under UV (365 nm) and blue (455 nm) LED irradiation, respectively. These findings provide direct evidence that the dramatic change in visible light absorbance of H-treated black TiO₂ is accompanied by significant hydrogen uptake and not just Ti³⁺ generation or surface disordering.

Original language	English
Pages (from-to)	35-43
Number of pages	9
Journal	Microporous and Mesoporous Materials
Volume	261
DOIs	https://doi.org/10.1016/j.micromeso.2017.10.036
State	Published - May 1 2018
Externally published	Yes

Funding

The authors acknowledge financial support from University of Kentucky faculty start-up funds (DYK) . The bulk of the film synthesis and characterization were performed under a National Science Foundation EPSCoR Research Infrastructure Initiative award (grant no. IIA-1355438 ). Neutron reflectometry measurements were carried out on the liquids reflectometer at the Spallation Neutron Source, which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. DOE . This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357 . Finally, the authors thank Prof. Y.T. Cheng; Prof. Dibakar Bhattacharyya and Andrew Colburn; and Prof. Brad Berron and Ishan Fursule for access to and assistance with the XPS, zeta potential, and contact angle measurements, respectively.

Keywords

Hydrogen doping
Mesoporous titania
Photocatalysis
Plasma treatment
Water splitting

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10.1016/j.micromeso.2017.10.036

Cite this

@article{c5a6322d4ddf4afca9dab02affa29f15,

title = "Hydrogen incorporation by plasma treatment gives mesoporous black TiO2 thin films with visible photoelectrochemical water oxidation activity",

abstract = "Neutron reflectometry (NR) is used to investigate the role of hydrogen in the visible light absorption and enhanced photoactivity for water oxidation of mesoporous black titania thin films. The cubic mesoporous frameworks of TiO2 thin films are prepared by a surfactant-templated sol-gel method and subsequently treated with hydrogen plasma, an approach hypothesized to capitalize on the high degree of disorder in the material and the high energy of the plasma species to achieve efficient hydrogen doping. UV-vis absorbance spectra indicate broad-spectrum visible light absorption in H2 plasma-treated black TiO2 films, and XPS indicates the generation of reduced Ti3+ in the treated films. The presence of hydrogen in black mesoporous titania (H-TiO2) films is confirmed by the scattering length density (SLD) profiles obtained from neutron reflectometry measurements. The H-TiO2 shows ca. 28 times and 8 times higher photocurrent for photoelectrochemical water oxidation compared to undoped TiO2 films under UV (365 nm) and blue (455 nm) LED irradiation, respectively. These findings provide direct evidence that the dramatic change in visible light absorbance of H-treated black TiO2 is accompanied by significant hydrogen uptake and not just Ti3+ generation or surface disordering.",

keywords = "Hydrogen doping, Mesoporous titania, Photocatalysis, Plasma treatment, Water splitting",

author = "Islam, {Syed Z.} and Allen Reed and Suraj Nagpure and Namal Wanninayake and Browning, {James F.} and Joseph Strzalka and Kim, {Doo Young} and Rankin, {Stephen E.}",

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year = "2018",

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doi = "10.1016/j.micromeso.2017.10.036",

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T1 - Hydrogen incorporation by plasma treatment gives mesoporous black TiO2 thin films with visible photoelectrochemical water oxidation activity

AU - Islam, Syed Z.

AU - Reed, Allen

AU - Nagpure, Suraj

AU - Wanninayake, Namal

AU - Browning, James F.

AU - Strzalka, Joseph

AU - Kim, Doo Young

AU - Rankin, Stephen E.

PY - 2018/5/1

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N2 - Neutron reflectometry (NR) is used to investigate the role of hydrogen in the visible light absorption and enhanced photoactivity for water oxidation of mesoporous black titania thin films. The cubic mesoporous frameworks of TiO2 thin films are prepared by a surfactant-templated sol-gel method and subsequently treated with hydrogen plasma, an approach hypothesized to capitalize on the high degree of disorder in the material and the high energy of the plasma species to achieve efficient hydrogen doping. UV-vis absorbance spectra indicate broad-spectrum visible light absorption in H2 plasma-treated black TiO2 films, and XPS indicates the generation of reduced Ti3+ in the treated films. The presence of hydrogen in black mesoporous titania (H-TiO2) films is confirmed by the scattering length density (SLD) profiles obtained from neutron reflectometry measurements. The H-TiO2 shows ca. 28 times and 8 times higher photocurrent for photoelectrochemical water oxidation compared to undoped TiO2 films under UV (365 nm) and blue (455 nm) LED irradiation, respectively. These findings provide direct evidence that the dramatic change in visible light absorbance of H-treated black TiO2 is accompanied by significant hydrogen uptake and not just Ti3+ generation or surface disordering.

AB - Neutron reflectometry (NR) is used to investigate the role of hydrogen in the visible light absorption and enhanced photoactivity for water oxidation of mesoporous black titania thin films. The cubic mesoporous frameworks of TiO2 thin films are prepared by a surfactant-templated sol-gel method and subsequently treated with hydrogen plasma, an approach hypothesized to capitalize on the high degree of disorder in the material and the high energy of the plasma species to achieve efficient hydrogen doping. UV-vis absorbance spectra indicate broad-spectrum visible light absorption in H2 plasma-treated black TiO2 films, and XPS indicates the generation of reduced Ti3+ in the treated films. The presence of hydrogen in black mesoporous titania (H-TiO2) films is confirmed by the scattering length density (SLD) profiles obtained from neutron reflectometry measurements. The H-TiO2 shows ca. 28 times and 8 times higher photocurrent for photoelectrochemical water oxidation compared to undoped TiO2 films under UV (365 nm) and blue (455 nm) LED irradiation, respectively. These findings provide direct evidence that the dramatic change in visible light absorbance of H-treated black TiO2 is accompanied by significant hydrogen uptake and not just Ti3+ generation or surface disordering.

KW - Hydrogen doping

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