Bai Long, Wang Jueyu, Yang Kuo, Yan Yi, Jin Meitong, Cui Daizong, Zhao Min
College of Life Science, Northeast Forestry University, Harbin, China.
Discov Nano. 2023 Feb 10;18(1):10. doi: 10.1186/s11671-023-03785-w.
Element doping is an important method for improving the performance levels of photoelectrochemical (PEC) cells. Nevertheless, to date, the PEC conversion efficiency and photocurrent characteristics of the available photoanodes remain very low. In this study, cobalt (Co) was selectively doped into the bottom and/or top layers of double-layered α-FeO nanorod arrays grown on conductive transparent substrates (F:SnO, FTO) via a two-step hydrothermal method; this process was performed to enhance the charge transfer ability and thus significantly improve the PEC performance. The light response capabilities of all α-FeO films were evaluated by an electrochemical workstation under dark or visible light irradiation conditions. The sample of Co doped in the bottom layer exhibited a high photoelectrochemical performance, achieving a current density of 1.37 mA/cm at + 1.0 V versus saturated calomel electrode (SCE); additionally, the sample exhibited a photoelectric synergistic ability to reduce Cr(VI) in an aqueous solution, with 84.85% reduction in 180 min. Under the influence of the electric field inside the double-layer electrode, the photoexcited electrons and holes are transferred to the surfaces of the FTO substrate and the photoanode, increasing the current density and enhancing Cr(VI) reduction. The results of this study offer an alternative approach for designing novel photoanodes with improved PEC performance levels by engineering the electron density distribution and band structure for efficient carrier separation; the results may provide new solutions in heavy metal reduction and contaminant degradation projects.
元素掺杂是提高光电化学（PEC）电池性能水平的重要方法。然而，迄今为止，现有光阳极的PEC转换效率和光电流特性仍然非常低。在本研究中，通过两步水热法将钴（Co）选择性地掺杂到生长在导电透明基板（F:SnO，FTO）上的双层α-FeO纳米棒阵列的底层和/或顶层；进行该过程以增强电荷转移能力，从而显著提高PEC性能。在黑暗或可见光照射条件下，通过电化学工作站评估所有α-FeO薄膜的光响应能力。底层掺杂Co的样品表现出高光电化学性能，在相对于饱和甘汞电极（SCE）为 +1.0 V时实现了1.37 mA/cm²的电流密度；此外，该样品在水溶液中具有还原Cr(VI)的光电协同能力，在180分钟内还原率为84.85%。在双层电极内部电场的影响下，光激发的电子和空穴转移到FTO基板和光阳极的表面，增加了电流密度并增强了Cr(VI)的还原。本研究结果为通过设计电子密度分布和能带结构以实现有效载流子分离来设计具有更高PEC性能水平的新型光阳极提供了一种替代方法；该结果可能在重金属还原和污染物降解项目中提供新的解决方案。
