Abstract

Tungsten oxide (WO₃) is a promising photoanode material capable of water oxidation under visible-light irradiation. Although WO₃ is usually prepared via sintering at 500 °C–550˚C, this work shows that high-temperature sintering (i.e., at 600 °C) can lead to efficient output at the WO₃ photoanode. The material characteristics such as the crystal system, surface structure, film thickness, and optical properties were essentially independent of the sintering temperatures employed. However, the high-temperature-sintered WO₃ showed low charge transfer resistance at the electrode–electrolyte interface, resulting in improved charge injection efficiency for water oxidation at the WO₃ photoanode. WO₃ sintered at 550 °C and 600 °C showed the similar visible Raman spectra with strong band intensities, indicative of improved crystallinity in WO₃ bulk particularly in the comparison with WO₃ sintered at 450 °C. However, the ultraviolet Raman spectrum exhibited intense bands for only the WO₃ prepared at 600 °C, indicating the enhanced crystallization of the WO₃ outermost surface. Thus, the high crystallinity in the WO₃ bulk and at its surface results in efficient photoanodic output owing to the suppression of electron–hole recombination.

Graphical Abstract

中文翻译：

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通过高温烧结增强氧化钨的光阳极活性和最外表面结晶度

摘要

氧化钨(WO₃)是一种很有前途的光阳极材料，能够在可见光照射下氧化水。虽然WO₃通常是通过在500°C–550°C下烧结来制备的，但这项工作表明高温烧结（即在600°C ）可以在 WO₃ 光电阳极实现高效输出。晶体系统、表面结构、薄膜厚度和光学性能等材料特性基本上与所采用的烧结温度无关。然而，高温烧结的WO₃在电极-电解质界面处表现出较低的电荷转移电阻，从而提高了水氧化的电荷注入效率。 WO₃ 光电阳极。在 550 °C 和 600 °C 下烧结的 WO₃ 显示出相似的可见拉曼光谱，但谱带强度较强，表明 WO 的结晶度得到改善₃ 体积较大，特别是与 WO₃ 相比，在 450 °C 下烧结。然而，只有在 600 °C 制备的 WO₃ 的紫外拉曼光谱显示出强谱带，表明 WO< a i=19>3最外层表面。因此，WO₃块体及其表面的高结晶度由于抑制电子空穴复合而导致有效的光阳极输出。

图形概要