Photoelectrochemical (PEC) water splitting offers a sustainable route for hydrogen production, leveraging noncritical semiconductor materials. This study introduces a seed layer-free hydrothermal synthesis approach for semiconductor photoanodes based on tungsten trioxide (WO₃) nanoplatelets. Aiming to boost the efficiency of photoelectrochemical water splitting through optimization of the synthesis parameters of bare WO₃, focusing on temperature, time, and layer thickness, we systematically explored their effects on the morphological, structural, and optical characteristics of WO₃ photoanodes. Combining a low-temperature regime (90 °C for 12 h) with a multilayer strategy (up to six-layers) resulted in significant improvements in photocurrent. Particularly, the five-layer sample exhibited a remarkable increase of over 70% compared to the single-layer photoanode. Morphological aspects, particularly the fractal dimension of nanoplatelets and the emergence of the (220) crystalline orientation, usually neglected, were found to play pivotal roles in modulating the PEC response. Rietveld refinement of X-ray diffraction patterns further underscored the importance of crystallographic facets, volume unit cell expansion, and microstrain in influencing photocurrent outcomes. Furthermore, we adapted the Mott–Schottky equation to incorporate the fractal dimension reflecting the nanostructures’ nature, usually set to a planar interface. Our findings highlight the interchange between nanoplatelet morphology and structural parameters in determining the PEC efficiency of WO₃ photoanodes.

中文翻译：

---

揭示水热 WO3 纳米片在光电化学太阳能水分解中的形态-结构相互作用


光电化学 （PEC） 水分解为利用非关键半导体材料为制氢提供了一种可持续的途径。本研究介绍了一种基于三氧化钨 （WO₃） 纳米片的半导体光阳极无种子层水热合成方法。旨在通过优化裸露 WO₃ 的合成参数来提高光电化学分解水的效率，重点关注温度、时间和层厚，我们系统地探讨了它们对 WO₃ 光阳极的形态、结构和光学特性的影响。将低温状态（90 °C 持续 12 小时）与多层策略（最多六层）相结合，可显著提高光电流。特别是，与单层光阳极相比，五层样品表现出超过 70% 的显着增加。形态学方面，特别是纳米片的分形维数和 （220） 晶向的出现，通常被忽视，被发现在调节 PEC 反应中起关键作用。X 射线衍射图谱的 Rietveld 细化进一步强调了晶体学刻面、体积单位细胞扩增和微应变在影响光电流结果中的重要性。此外，我们调整了 Mott-Schottky 方程，以纳入反映纳米结构性质的分形维数，通常设置为平面界面。我们的研究结果强调了纳米片形态和结构参数在确定 WO₃ 光阳极的 PEC 效率方面的互换。