Synthesis of hierarchical WO₃ microspheres for photoelectrochemical water splitting application

In this work, hierarchical WO₃ microspheres were synthesized using chemical bath deposition. The morphology of the synthesized sample was studied using scanning electron microscopy (SEM). The hierarchical WO₃ microspheres formed from spontaneously self-assembled nanosheets have a high specific surface area. Structural characterizations of sample were performed using X-ray diffraction (XRD) and Raman spectroscopy. Analysis of XRD spectra showed that synthesized particles have a monoclinic modification. The optical properties of the sample were studied using UV-Vis diffuse reflectance absorption spectra. The value of the energy gap calculated from the absorption spectra is 2.25 eV, which indicates high light absorption ability. A photocurrent study was done to investigate the photocatalytic activity. The photoelectrode was prepared using hierarchical WO₃ microspheres and polymer deposited on fluorine doped tin oxide (FTO) glass via spin coating technique. A remarkable photocurrent density of 18 A/cm² at 0.5 V was achieved. The elongated structures improved light absorption ability and photocatalytic activity, and might be perspective as photoanode in photoelectrochemical cells.