Realization of high photocatalytic hydrogen generation activity by nanostructured Ga1−xZnxO1−zNz solid-solution without co-catalyst
Realization of high photocatalytic hydrogen generation activity by nanostructured Ga1−xZnxO1−zNz solid-solution without co-catalyst
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DOI：
10.1016/j.ijhydene.2015.07.156
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发表时间：
2015-10
影响因子：
7.2
通讯作者：
S. Menon;B. Kuppulingam;K. Baskar;T. Sairam;T R Ravindran;B. Gupta;Shubra Singh
中科院分区：
文献类型：
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作者：
S. Menon;B. Kuppulingam;K. Baskar;T. Sairam;T R Ravindran;B. Gupta;Shubra Singh
光催化需要光吸收以及光生电子-空穴对到化学活性位点的有效提取。为了避免电子空穴复合，我们需要定制的纳米结构，可以表现出新的光吸收和热力学性质。这项工作表明，由于固溶体的形成而导致的带隙改性/变窄沿着纳米结构的表面积增加对于太阳能收集是理想的，并且即使在不存在助催化剂的情况下也是自给自足的光催化剂。本研究表明，在可见光照射下（>400 nm），即使没有助催化剂，GaN固溶体的产氢速率也可忽略不计，达到32.43 μmol/g/h。H2释放的表观量子产率（AQY）效率为0.8%。这种非常理想的增加的H2生成活性归因于纳米结构纤锌矿Ga 1-xZnxO 1-zNz固溶体的光致发光光谱中的额外线宽增宽，这是由于Ga/Zn和N/O相互扩散引起晶格中的修改的带隙和N2 p-O2 p相互作用。这些推论也证实了样品的漫反射光谱。首次讨论了低能拉曼谱中出现的一些未报道的弱特征的来源。一系列的表征工具，包括结构，微观结构，光学，光谱和光催化制氢的研究，以支持我们的索赔。
Photocatalysis requires light absorption as well as efficient extraction of the photogenerated electron–hole pairs to chemically active sites. To avoid electron–hole recombination, we need tailored nanostructures which can demonstrate novel light absorption and thermodynamic properties. This work shows that band gap modification/narrowing due to the formation of solid solution along with an increased surface area of the nanostructures are ideal for solar harvesting and is a self sufficient photocatalytic agent even in absence of a co-catalyst. The present study suggests that the rate of H2production for GaN was negligible and it increased to 32.43 μmol/g/h for the solid solution under visible light irradiation (>400 nm) even in the absence of a co-catalyst. The apparent quantum yield (AQY) efficiency of H2evolution was found to be 0.8%. This highly desirable increased H2generation activity is attributed to the additional linewidth broadening in the photoluminescence spectra of nanostructured wurtzite Ga1−xZnxO1−zNzsolid-solution due to Ga/Zn and N/O interdiffusion giving rise to a modified bandgap and N2p-O2p interaction in the lattice. These inferences are also corroborated by diffuse reflectance spectra of the samples. For the first time, origin of hitherto unreported weak features appearing in the low energy Raman spectrum is also discussed. A series of characterization tools including structural, microstructural, optical, spectroscopic and Photocatalytic hydrogen production studies were employed to support our claim.