The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science & Technology, Wuhan 430081, P. R. China.
Chem Commun (Camb). 2019 Sep 19;55(76):11382-11385. doi: 10.1039/c9cc05331j.
The construction of a nano-heterojunction photoanode is an attractive strategy for accelerated charge separation. Here, α-Fe2O3 nanorod arrays (Fe2O3 NAs) top-decorated with an MIL-101 layer are achieved via the CVD method for constructing one intimate contact between two layers. The systematical analysis in time-dependent deposition shows that the photoelectric response capability can be modulated by controlling the thickness of the MIL-101 layer as a function of CVD duration. An optimized thickness of 4-6 nm MIL-101 in the Fe2O3/MIL-101 photoanode presents the best PEC performance with the IPCE of 25% and a photocurrent density of 1 mA cm-2 at 1.3 V vs. RHE, about 2.5 times higher than that of pristine Fe2O3 NAs. The exciton lifetime and the electrochemical active surface area of the composited electrode are greatly improved by 14 and 1.3 times respectively compared to that of pristine Fe2O3. The notable advancement can be attributed to the fact that the top-decorated MOF layer can promote charge separation efficiency led by the built-in electric field and form a tight interface between Fe2O3 and MIL-101 with a favorable diffusion length for holes, as well as the fact that it can reduce surface defects and provide more reaction sites.
构建纳米异质结光阳极是加速电荷分离的一种有吸引力的策略。在这里，通过 CVD 方法实现了 α-Fe2O3 纳米棒阵列 (Fe2O3 NAs) 的顶部修饰有 MIL-101 层，以实现两层之间的紧密接触。随着时间的推移进行的系统分析表明，光电响应能力可以通过控制 MIL-101 层的厚度来调节，其厚度作为 CVD 持续时间的函数。在 Fe2O3/MIL-101 光阳极中，优化的 4-6nm MIL-101 厚度表现出最佳的 PEC 性能，在 1.3V 相对于 RHE 时的 IPCE 为 25%，光电流密度为 1mA cm-2，比原始的 Fe2O3 NAs 高约 2.5 倍。与原始的 Fe2O3 相比，复合电极的激子寿命和电化学活性表面积分别提高了 14 倍和 1.3 倍。显著的进展可以归因于以下事实：顶部修饰的 MOF 层可以通过内置电场促进电荷分离效率，并在 Fe2O3 和 MIL-101 之间形成紧密的界面，具有有利于空穴扩散的长度，并且它可以减少表面缺陷并提供更多的反应位点。
