The 3D flower-like WO3 nanoparticles with hierarchical structures were synthesized via a hydrothermal synthesis technique by using NaHSO4 as a capping agent. It demonstrates that surface area of the synthesized WO3 products can be manipulated via adjusting concentration of the capping agent NaHSO4 alone. The contribution of alcohol is to construct hierarchical structures with large specific surface areas, while the effect of SO42- is to inhibit the growth rate in the thickness direction of nanosheets which are self-assembled as well to form hierarchical structures. In addition, the gas-sensing...
