Investigations of the electrochemical stability of InGaN photoanodes in different electrolytes
Investigations of the electrochemical stability of InGaN photoanodes in different electrolytes
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DOI：
10.1002/pssb.201451576
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发表时间：
2015-05
期刊：
影响因子：
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通讯作者：
M. Finken;A. Wille;B. Reuters;M. Heuken;H. Kalisch;A. Vescan
中科院分区：
文献类型：
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作者：
M. Finken;A. Wille;B. Reuters;M. Heuken;H. Kalisch;A. Vescan
InGaN是一种很有前途的材料，直接太阳能水分解，由于其可调的带隙在0.69和3.4 eV之间。最近进行了几项研究，以测试InGaN在光电化学电池（佩奇）中的适用性。这些研究是在多种不同的电解质中进行的，因此结果的比较非常困难。因此，本工作研究并比较了InGaN在不同常用电解液中的电化学稳定性。InGaN层通过金属有机气相外延（MOVPE）沉积。通过高分辨率X射线衍射（HRXRD）、原子力显微镜（AFM）和扫描电子显微镜（SEM）检查了它们的结构性质。InGaN层的长期稳定性在NaCl、HCl、HBr、H2SO 4、NaOH和KOH中进行了研究。48小时后观察两种基底的蚀刻。此外，通过计时电流法研究了光阳极。对于这些测量，用55 W氙灯照射样品45 min，并另外用0.5 V偏置。不同电解质的比较表明，只有NaOH和HBr中的样品显示出足够的光电流。此外，仅在1 mol/L NaCl和1 mol/L HBr中观察到稳定的InGaN表面。由于HBr的使用很可能导致形成Br 2而不是O2，因此可以得出结论，在佩奇中必须使用n掺杂InGaN与助催化剂以防止表面蚀刻。
InGaN is a promising material for direct solar water splitting due to its tuneable bandgap between 0.69 and 3.4 eV. Several investigations were carried out recently to test the suitability of InGaN in photoelectrochemical cells (PECs). These studies were performed in a multitude of different electrolytes and hence a comparison of the results is very difficult. Therefore, the electrochemical stability of InGaN was investigated and compared in different commonly used electrolytes in this work. The InGaN layers were deposited via metal‐organic vapour phase epitaxy (MOVPE). Their structural properties were examined by high‐resolution X‐ray diffraction (HRXRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). The long‐term stability of the InGaN layers was studied in NaCl, HCl, HBr, H2SO4, NaOH and KOH. Etching was observed for the two bases after 48 h. Furthermore, the photoanodes were investigated via chronoamperometry. For these measurements, the samples were illuminated with a 55 W Xe lamp for 45 min and additionally biased with 0.5 V. A comparison of the different electrolytes reveals that only the samples in NaOH and HBr show a sufficient photocurrent. Additionally, stable InGaN surfaces were observed only in 1 mol/L NaCl and in 1 mol/L HBr. Since the use of HBr most likely leads to the formation of Br2 instead of O2, it is concluded that n‐doped InGaN has to be used with co‐catalysts in PECs to prevent the etching of the surface.