Nickel and either tantalum or niobium-codoped TiO2 and SrTiO3 photocatalysts with visible-light response for H2 or O2 evolution from aqueous solutions.
Nickel and either tantalum or niobium-codoped TiO2 and SrTiO3 photocatalysts with visible-light response for H2 or O2 evolution from aqueous solutions.
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DOI：
10.1039/b502147b
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发表时间：
2005-05
期刊：
影响因子：
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通讯作者：
Ryo Niishiro;H. Kato;A. Kudo
中科院分区：
文献类型：
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作者：
Ryo Niishiro;H. Kato;A. Kudo
在可见光照射(波长420 nm)下，共掺镍和钽或铌离子的二氧化钛(带隙=3.0 eV)和钛酸锶(带隙=3.2 eV)对硝酸银溶液析氧和甲醇水溶液析氢具有光催化活性。可见光响应是由掺杂Ni2+的3d轨道形成的电子给体能级向基质材料导带的电荷转移引起的。Ta、Nb离子的共掺杂使掺杂镍离子的TiO2光催化剂在可见光范围内的吸收强度增强，从而提高了可见光照射下的光催化析氧活性。镍和钽共掺杂的钛酸锶表现出比单掺镍的钛酸锶更高的析氢活性。这是因为共掺杂的Ta5+离子起到了电荷补偿的作用，导致Ni3+离子的形成受到抑制，Ni3+离子有望捕获光生电子。
TiO2 (band gap = 3.0 eV) and SrTiO3 (band gap = 3.2 eV) codoped with nickel and either tantalum or niobium ions showed photocatalytic activities for O2 evolution from an aqueous silver nitrate solution and H2 evolution from an aqueous methanol solution under visible light irradiation (lambda > 420 nm). The visible-light responses were due to the charge-transfer transition from the electron donor levels formed by the 3d orbitals of doped Ni2+ to the conduction bands of the host materials. Codoping of a tantalum or niobium ion made the absorption intensity in the visible light region strong for TiO2 doped with nickel ions, resulting in the enhancement of the photocatalytic activity for O2 evolution under visible light irradiation. SrTiO3 codoped with nickel and tantalum showed higher activity for H2 evolution than SrTiO3 doped with only nickel. This is due to the fact that codoped Ta5+ ions played a role in charge compensation, resulting in the suppression of the formation of Ni3+ ions, which are expected to trap photogenerated electrons.