Photocatalytic activity of LaTaON 2 powders prepared using an oxide precursor derived from a hydrothermal reaction
Photocatalytic activity of LaTaON 2 powders prepared using an oxide precursor derived from a hydrothermal reaction
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DOI：
10.14723/tmrsj.40.275
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发表时间：
2015-09
期刊：
影响因子：
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通讯作者：
Mai Takasaki;Chihiro Izawa;Kazuhisa Kishida;Tomoaki Watanabe
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文献类型：
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作者：
Mai Takasaki;Chihiro Izawa;Kazuhisa Kishida;Tomoaki Watanabe
为提高其在可见光照射下对甲醇水溶液的光催化析氢活性，采用水热法合成片状LaTaO 4前驱体，通过氮化反应制备片状LaTaON 2。水热法制备的LaTaON 2样品仅由5 ~ 10 μm的微团聚颗粒组成。而固相反应法制备的LaTaON 2样品则是由0.5 ~ 1.5 μm的不规则聚集的初级颗粒组成。对于以Pt为助催化剂的光催化放氢反应，片状LaTaON 2比不规则形状的LaTaON 2具有更高的光催化活性.此外，紫外-可见漫反射光谱表明，与不规则形状的LaTaON 2相比，板状LaTaON 2由于阴离子空位或还原的Ta 5+物种的存在而具有较低的缺陷密度，如在较长波长（λ > 660 nm）处的吸收强度降低所证明的那样。因此，使用水热法合成的LaTaO 4前体，我们得到了LaTaON 2与减少的缺陷，作为光生载流子的复合中心的密度。
Plate-like LaTaON 2 was prepared by the nitridation of plate-like LaTaO 4 precursor synthesized by hydrothermal method to improve the photocatalytic activity for H 2 evolution from an aqueous methanol solution under visible light irradiation. LaTaON 2 samples derived from hydrothermal method consisted of only slightly aggregated particles 5 –10 μm in size. In contrast, LaTaON 2 samples derived from solid-state reaction method consisted of irregular-shaped and aggregated primary particles 0.5 –1.5 μm in size. For photocatalytic H 2 evolution using Pt as a co-catalyst, plate-like LaTaON 2 exhibited higher photocatalytic activity than irregular-shaped LaTaON 2 . In addition, ultraviolet-visible diffuse reflectance spectra suggested that plate-like LaTaON 2 had a lower density of defects due to the presence of anion vacancies or reduced Ta 5+ species than irregular-shaped LaTaON 2 , as demonstrated by the reduced intensity of absorption at longer wavelengths (λ > 660 nm). Therefore, using a LaTaO 4 precursor synthesized by hydrothermal method, we obtained LaTaON 2 with reducing the density of defects that act as recombination centers for photogenerated carriers.