Gallium oxynitride photocatalysts synthesized from Ga(OH)3 for water splitting under visible light irradiation

Che Chia Hu; Hsisheng Teng

doi:10.1021/jp1070083

Gallium oxynitride photocatalysts synthesized from Ga(OH)₃ for water splitting under visible light irradiation

Che Chia Hu, Hsisheng Teng

Department of Chemical Engineering

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

70 Citations (Scopus)

Abstract

We report the synthesis of wurtzite-like gallium oxynitride (GaON) photocatalysts by nitridation of Ga(OH)₃ with NH₃ at temperatures between 550 and 900 °C. Ga(OH)₃ is a more suitable precursor for GaON synthesis than Ga₂O₃, because its crystal lattice contains unoccupied 12-coordinate sites that facilitate ionic transportation during nitridation. The prepared GaON catalysts had band gap energies from 2.2 to 2.8 eV and showed significant activities in the visible-light promoted evolution of H₂ and O₂ gases from methanol and AgNO₃ solutions, respectively. The maximum H₂ and O₂ evolution rates occurred for catalysts synthesized at 625 and 700 °C, respectively. These active catalysts had an N/O atomic ratio close to unity, suggesting that extensive hybridization of N_2p and O _2p orbitals promotes charge mobility, and thus enhances photocatalytic activity. This study highlights the interesting possibility of synthesizing a large diversity of visible-light active, III-oxynitride catalysts using this Ga(OH)₃ route.

Original language	English
Pages (from-to)	20100-20106
Number of pages	7
Journal	Journal of Physical Chemistry C
Volume	114
Issue number	47
DOIs	https://doi.org/10.1021/jp1070083
Publication status	Published - 2010 Dec 2

All Science Journal Classification (ASJC) codes

Electronic, Optical and Magnetic Materials
General Energy
Physical and Theoretical Chemistry
Surfaces, Coatings and Films

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10.1021/jp1070083

Cite this

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title = "Gallium oxynitride photocatalysts synthesized from Ga(OH)3 for water splitting under visible light irradiation",

abstract = "We report the synthesis of wurtzite-like gallium oxynitride (GaON) photocatalysts by nitridation of Ga(OH)3 with NH3 at temperatures between 550 and 900 °C. Ga(OH)3 is a more suitable precursor for GaON synthesis than Ga2O3, because its crystal lattice contains unoccupied 12-coordinate sites that facilitate ionic transportation during nitridation. The prepared GaON catalysts had band gap energies from 2.2 to 2.8 eV and showed significant activities in the visible-light promoted evolution of H2 and O2 gases from methanol and AgNO3 solutions, respectively. The maximum H2 and O2 evolution rates occurred for catalysts synthesized at 625 and 700 °C, respectively. These active catalysts had an N/O atomic ratio close to unity, suggesting that extensive hybridization of N2p and O 2p orbitals promotes charge mobility, and thus enhances photocatalytic activity. This study highlights the interesting possibility of synthesizing a large diversity of visible-light active, III-oxynitride catalysts using this Ga(OH)3 route.",

author = "Hu, {Che Chia} and Hsisheng Teng",

year = "2010",

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doi = "10.1021/jp1070083",

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T1 - Gallium oxynitride photocatalysts synthesized from Ga(OH)3 for water splitting under visible light irradiation

AU - Hu, Che Chia

AU - Teng, Hsisheng

PY - 2010/12/2

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N2 - We report the synthesis of wurtzite-like gallium oxynitride (GaON) photocatalysts by nitridation of Ga(OH)3 with NH3 at temperatures between 550 and 900 °C. Ga(OH)3 is a more suitable precursor for GaON synthesis than Ga2O3, because its crystal lattice contains unoccupied 12-coordinate sites that facilitate ionic transportation during nitridation. The prepared GaON catalysts had band gap energies from 2.2 to 2.8 eV and showed significant activities in the visible-light promoted evolution of H2 and O2 gases from methanol and AgNO3 solutions, respectively. The maximum H2 and O2 evolution rates occurred for catalysts synthesized at 625 and 700 °C, respectively. These active catalysts had an N/O atomic ratio close to unity, suggesting that extensive hybridization of N2p and O 2p orbitals promotes charge mobility, and thus enhances photocatalytic activity. This study highlights the interesting possibility of synthesizing a large diversity of visible-light active, III-oxynitride catalysts using this Ga(OH)3 route.

AB - We report the synthesis of wurtzite-like gallium oxynitride (GaON) photocatalysts by nitridation of Ga(OH)3 with NH3 at temperatures between 550 and 900 °C. Ga(OH)3 is a more suitable precursor for GaON synthesis than Ga2O3, because its crystal lattice contains unoccupied 12-coordinate sites that facilitate ionic transportation during nitridation. The prepared GaON catalysts had band gap energies from 2.2 to 2.8 eV and showed significant activities in the visible-light promoted evolution of H2 and O2 gases from methanol and AgNO3 solutions, respectively. The maximum H2 and O2 evolution rates occurred for catalysts synthesized at 625 and 700 °C, respectively. These active catalysts had an N/O atomic ratio close to unity, suggesting that extensive hybridization of N2p and O 2p orbitals promotes charge mobility, and thus enhances photocatalytic activity. This study highlights the interesting possibility of synthesizing a large diversity of visible-light active, III-oxynitride catalysts using this Ga(OH)3 route.

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