Department of Chemistry, Faculty of Science, Hakim Sabzevari University, P. O. Box 397, Sabzevar, Iran.
Department of Physics, Faculty of Science, Hakim Sabzevari University, P. O. Box 397, Sabzevar, Iran.
Chemosphere. 2024 Jan;346:140579. doi: 10.1016/j.chemosphere.2023.140579. Epub 2023 Oct 27.
Molybdenum-doped BiVO thin films were uniformly coated on indium-doped tin oxide (ITO) substrates via a facile modified hot spin coating (HSC) technique. The prepared layers were used as photoanode in a photoelectrochemical (PEC) cell. Different percentage of Mo dopant was examined to maximize the photo-current density (J) of the layers. The highest J value (872 ± 8 μA/cm) was obtained by 5 atomic% of Mo doping. After that, the surface topographies of these samples were changed by varying the initial precursor concentration from 27 to 80 mM. The relation between surface topographies and the PEC activity of Mo-doped BiVO thin films was investigated from microscopic point of view by calculating the surface roughness exponent of α, and a mechanism for the PEC activity of Mo-doped BiVO photoanodes was proposed accordingly. The sample with a small roughness exponent provided a surface with jagged microscopic fluctuations which may trap the air molecules between the electrolyte and sample surface, hindering the fine atomic interaction for photo-generated electron-hole transition. Therefore, the layer with the highest roughness exponent (2α = 0.48 ± 0.03), which means the smoother microscopic surface and better interfacial contact with the electrolyte, exhibited the best PEC activity.
钼掺杂的 BiVO 薄膜通过简便的改进热旋转涂层（HSC）技术均匀地涂覆在掺锡氧化铟（ITO）衬底上。所制备的层用作光电化学（PEC）电池的光阳极。研究了不同比例的 Mo 掺杂剂，以最大化层的光电流密度（J）。通过 5 原子%的 Mo 掺杂获得了最高的 J 值（872±8μA/cm）。之后，通过将初始前体浓度从 27mM 变化到 80mM，改变了这些样品的表面形貌。通过计算表面粗糙度指数α，从微观角度研究了 Mo 掺杂 BiVO 薄膜的表面形貌与 PEC 活性之间的关系，并相应地提出了 Mo 掺杂 BiVO 光阳极的 PEC 活性机制。具有较小粗糙度指数的样品提供了具有锯齿状微观波动的表面，这可能会在电解质和样品表面之间捕获空气分子，阻碍光生电子空穴跃迁的精细原子相互作用。因此，具有最高粗糙度指数（2α=0.48±0.03）的层，意味着更平滑的微观表面和与电解质更好的界面接触，表现出最佳的 PEC 活性。
