A Fe₃O₄/Fe₂O₃ photoelectrode exhibiting excellent broadband and light-trapping characteristics has been prepared. It is found to be of unique multi-scale structure that is composed of pyramids from 5 to 10 μm in width grown on nanorod arrays from 400 to 500 μm in diameter. This multi-scale structure displays an extraordinary surface catalytic-activity and photothermal effect, which result in strong absorption in UV–Vis–NIR region and significantly improved PEC performance. Besides, type II p-n Fe₂O₃/Fe₃O₄ heterojunction with suitable energy position and its built-in electric field favor separation and transfer of photogenerated carriers. The optimized Fe₂O₃/Fe₃O₄ photoanode therefore exhibits a much larger photocurrent density ∼0.68 mA/cm² at 1.23 V vs. RHE under simulated sunlight illumination compared to 0.08 mA/cm² of the pure Fe₂O₃ photoelectrode. This unique design for multi-scale structure may provide a route to develop high-efficient photoelectrode with full-spectrum response.

制备了具有优异宽带和光俘获特性的Fe ₃ O ₄ /Fe ₂ O _{3光电极。}它被发现具有独特的多尺度结构，由生长在直径 400 至 500 微米的纳米棒阵列上的宽度为 5 至 10 微米的金字塔组成。这种多尺度结构显示出非凡的表面催化活性和光热效应，从而在 UV-Vis-NIR 区域产生强烈吸收并显着提高 PEC 性能。此外，II型pn Fe ₂ O ₃ /Fe ₃ O ₄具有合适能量位置的异质结及其内建电场有利于光生载流子的分离和转移。因此，优化后的 Fe ₂ O ₃ /Fe ₃ O ₄光电阳极在1.23 V 时表现出更大的光电流密度～0.68 mA/cm ² 模拟日光照射下的 RHE 与纯 Fe ₂ O _{3光电极的 0.08 mA/cm} ²相比。这种独特的多尺度结构设计可能为开发具有全光谱响应的高效光电极提供途径。