Spray Pyrolysis Deposition and Photoelectrochemical Properties of n-Type BiOI Nanoplatelet Thin Films
Spray Pyrolysis Deposition and Photoelectrochemical Properties of n-Type BiOI Nanoplatelet Thin Films
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DOI：
10.1021/nn3031063
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发表时间：
2012-09-01
期刊：
影响因子：
17.1
通讯作者：
Mullins, C. Buddie
中科院分区：
文献类型：
--
作者：
Hahn, Nathan T.;Hoang, Son;Mullins, C. Buddie
碘氧化铋是一种潜在的可见光催化剂，但对其光电化学性质的研究很少。在此，我们报告的BiOI纳米片光电极的合成通过喷雾热解氟掺杂的氧化锡基板在不同的温度下。薄膜表现出n型导电性，最有可能是由于阴离子空位的存在下，和优化的薄膜具有超过20%的入射光子转换效率在可见光范围内的氧化I-到I-3（-）在0.4 V与Ag/AgCl在乙腈中。可见光光子（λ>420 nm）在AM 1.5G照明下贡献了总光电流的约75%，说明了它们在太阳光照明下的有用性。发现260摄氏度的沉积温度由于形态、结晶度、杂质水平和光学吸收的平衡而导致最佳性能，导致在0.4V（相对于Ag/AgCl）下的光电流约为0.9mA/cm（2）。虽然膜在乙腈中稳定地进行，但它们的性能在延长暴露于水时显著下降，这显然是由表面碘的损失和随后形成的绝缘氢氧化铋层引起的。
Bismuth oxy-iodide is a potentially interesting visible-light-active photocatalyst; yet there is little research regarding its photoelectrochemical properties. Herein we report the synthesis of BiOI nanoplatelet photoelectrodes by spray pyrolysis on fluorine-doped tin oxide substrates at various temperatures. The films exhibited n-type conductivity, most likely due to the presence of anion vacancies, and optimized films possessed incident photon conversion efficiencies of over 20% in the visible range for the oxidation of I- to I-3(-) at 0.4 V vs Ag/AgCl in acetonitrile. Visible-light photons (lambda >420 nm) contributed approximately 75% of the overall photocurrent under AM1.5G illumination, illustrating their usefulness under solar light illumination. A deposition temperature of 260 degrees C was found to result in the best performance due to the balance of morphology, crystallinity, impurity levels, and optical absorption, leading to photocurrents of roughly 0.9 mA/cm(2) at 0.4 V vs Ag/AgCl. Although the films performed stably in acetonitrile, their performance decreased significantly upon extended exposure to water, which was apparently caused by a loss of surface iodine and subsequent formation of an insulating bismuth hydroxide layer.