In this work, for the first time, bismuth sulfide (Bi2S3) film formed on the stainless steel mesh surface as a suitablesubstrate.Differentfilmsweresynthesizedbyvariouscombinationsofthetwomethods(sonochemistry andelectrochemistry)incontinuousandpulsemodes.TheBi2S3filmscharacterizedbyX-rayDiffraction(XRD), ScanningElectronMicroscopy(SEM),EnergyDispersiveX-raySpectroscopy(EDS)andAtomicForceMicroscope (AFM). To reach the best film for photocatalytic reduction of Cr (VI), different films were deposited on the substrate by changing three independent variables including pulse times (ton, toff) and sonication amplitude. Response Surface Methodology (RSM) applied for optimization of independent variables by using Central Composite Design (CCD). Here, the films prepared by sono-electrodeposition in pulse modes led to high photocatalytic efficiency in comparison with other films. The results confirmed that ultrasound affected the morphology of film due to the production of cavitation, micro jets and acoustic streaming. On the other hand, ultrasounddecreaseddoublelayerthicknessanddissolveddiffusionproblems.Sono-electrodepositioninpulse modes produced films with pumice and fractal like structures. The high photocatalytic activity attributed to specialmorphologiesthathavekeyrolesinseparationofhole/electronpairsandlightmulti-scattering.

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