Gram‐Scale Synthesis of Ultrathin Tungsten Oxide Nanowires and Their Aspect Ratio‐Dependent Photocatalytic Activity

Preparation of size‐tunable ultrathin W18O49 nanowires by an alcohol‐assisted solvothermal decomposition of tungstic acid is reported. The synthesis of ultrathin W18O49 nanowires can be achieved at large scale and low cost, while changing the molecular size of the used alcohols can control the nanowire morphology. With increasing the molecular size of the alcohol, the synthesized W18O49 nanowires have smaller diameters and longer lengths. The as‐prepared blue W18O49 nanomaterials show a very strong visible light absorption caused by oxygen defects and an aspect ratio‐dependent photocatalytic activity on the degradation of pollutant rhodamine B (RhB) under simulated solar light irradiation. It is found that the W18O49 nanowires with highest aspect ratio show the highest activity in the photodegradation of RhB, which could be related to their higher density of oxygen surface defects in combination with a higher adsorption capability of RhB. This new synthetic route of size tunable ultrathin W18O49 nanomaterials will enlarge their potential applications and can be possibly used in the pyrolyzing synthesis of other metal oxide nanomaterials.