Tungsten oxide nanoparticles are particularly suitable for a wide range of applications like non-invasive cancer treatment, water treatment, gas sensing, and so on. In this paper, the effect of the solution pH on as-synthesized WO₃ nanoparticles and calcined WO₃ nanostructures at 500 °C is investigated to achieve appropriate WO₃ nanoparticles with a simple and low-price sol-gel method. The results declare that solution pH significantly affects the morphology, crystallinity, chemical bonds, and optical properties of WO₃ nanoparticles. Increasing solution pH from 1 to 2 with the step of 0.5 leads to crystal phase transition and increment of the hexagonal phase percentage. The size of nanoparticles increases with increasing the solution pH in as-synthesized. So, it turns out that solution pH affects the particles growth process. In addition, the results reveal that increasing the solution pH leads to a blue shift at the optical absorption edges. Also, the indirect energy bandgap of WO₃ particles increases/decreases with increasing pH in the case of as-synthesized/calcined samples. The energy bandgaps of calcined samples were generally lower than as-synthesized ones. The sample prepared at pH = 1 shows the highest absorption (about ten times higher than other samples at λ = 300 nm) and low reflection in the whole range of the spectrum that makes it a worthy candidate for photocatalysis applications.

氧化钨纳米颗粒特别适用于广泛的应用，如非侵入性癌症治疗、水处理、气体传感等。在本文中，研究了溶液 pH 值对500 °C下合成的 WO ₃纳米颗粒和煅烧的 WO ₃纳米结构的影响，以通过简单且价格低廉的溶胶-凝胶方法获得合适的 WO ₃纳米颗粒。结果表明，溶液 pH 显着影响 WO ₃的形态、结晶度、化学键和光学性质纳米粒子。以 0.5 为步长将溶液 pH 从 1 增加到 2 导致晶相转变和六方相百分比的增加。纳米粒子的尺寸随着合成中溶液 pH 值的增加而增加。因此，事实证明溶液 pH 值会影响颗粒生长过程。此外，结果表明，增加溶液 pH 值会导致光吸收边缘发生蓝移。此外，WO ₃的间接能带隙在合成/煅烧样品的情况下，颗粒随着 pH 值的增加而增加/减少。煅烧样品的能带隙通常低于合成样品。在 pH = 1 下制备的样品在整个光谱范围内表现出最高的吸收率（在 λ = 300 nm 处比其他样品高约十倍）和低反射，使其成为光催化应用的一个有价值的候选者。