Effect of solution chemistry on the characteristics of hydrothermally grown WO3 for electroactive applications

• Hydrothermally grown WO3 coatings with controlled properties.
• The choice of metal sulfate is important in determining their properties.
• Flower-like hexagonal WO3 structures for electroactive applications.

Hydrothermally grown tungsten trioxide coatings were prepared at 95 °C using different metal sulfates. Morphology of the oxides was altered from grains to flower- and urchin-like structures using potassium sulfate, sodium sulfate and lithium sulfate, respectively. The flower-like structures presented the highest deintercalated charge, 35 mC cm− 2 with time response of 96 s. In addition, they indicated a charge transfer resistance across the tungsten trioxide–electrolyte interface of 752 Ω. These outcomes imply that they are promising candidates for electroactive applications.