Flame vapor deposition processNucleation/growth rates controlNano-branch growth controlNanotree structured WO3 thin filmWO3/BiVO4 heterojunction thin filmPhotoelectrochemical applicationsTUNGSTEN-OXIDE NANOSTRUCTURESPHOTOCATALYTIC ACTIVITYWATER OXIDATIONTHIN-FILMSPHOTOANODESTRIOXIDEBIVO4PHOTOELECTROLYSISHETEROJUNCTIONSMODULATION