Abstract

Photoelectrocatalytic (PEC) water splitting technology is used to convert solar energy into hydrogen energy, and has the potential to alleviate energy crisis problem. TiO₂ nanowire arrays (NAs), as a promising PEC photoanode, have the advantages of low cost and stable mechanical properties. However, due to its wide energy band, poor conductivity, and slow carrier transfer kinetics, modifying TiO₂ NAs with metal is a feasible way to achieve high PEC performance, especially cobalt-based compounds. Different from the fussy and polluted synthesizing methods, here, we use a facile method to successfully load Co₃O₄ and CoO mixtures on TiO₂ NAs. A series of characterization methods are conducted to study the morphology, structure, and PEC water oxidation performance. It is found that the photocurrent density of the obtained CoO-Co₃O₄/TiO₂ photoelectrode is enhanced and good stability can be kept up for 13 h or more. The prominent reason for enhanced PEC performance of CoO-Co₃O₄/TiO₂ NAs is that loading CoO and Co₃O₄ can increase the light absorption, reduce the charge transfer resistance, and improve the charge separation efficiency of TiO₂ NAs. Our work introduces an alternative designing way to load both of CoO and Co₃O₄ on photoelectrode in a particularly eco-benign way, which provides efficient and stable cobalt-based TiO₂ photoanodes, and it can be applied to wider research fields, such as solar cells and photo-responsive devices.

Graphical abstract

摘要

光电催化（PEC）分解水技术用于将太阳能转化为氢能，具有缓解能源危机问题的潜力。TiO ₂纳米线阵列（NAs）作为一种有前途的PEC光电阳极，具有低成本和稳定的机械性能的优点。然而，由于其宽的能带，较差的电导率和较慢的载流子传输动力学，用金属改性TiO ₂ NAs是实现高PEC性能的可行方法，尤其是钴基化合物。与繁琐和污染的合成方法不同，这里我们使用一种简便的方法成功地将Co ₃ O ₄和CoO混合物负载到TiO _2上NAs。进行了一系列表征方法，以研究形态，结构和PEC水的氧化性能。发现所获得的CoO-Co ₃ O ₄ / TiO ₂光电极的光电流密度提高，并且可以保持良好的稳定性13小时以上。增强CoO-Co ₃ O ₄ / TiO ₂ NAs的PEC性能的突出原因是负载CoO和Co ₃ O ₄可以增加光吸收，降低电荷转移阻力，并提高TiO ₂ NAs的电荷分离效率。我们的工作介绍了一种替代设计方式，可同时加载CoO和Co ₃光电极上的O ₄以特别生态友好的方式提供了有效且稳定的钴基TiO ₂光电阳极，可应用于更广泛的研究领域，例如太阳能电池和光敏器件。