Surface heterojunction engineering has been extensively studied to promote efficient charge separation in semiconductor materials.Designing an effective heterojunction system to optimize the separation and transport of photo-induced charges is an appealing strategy to enhance the photocatalytic efficiency.In this work,In2O3-x(OH)y in situ decorated Bi2MoO6 two-dimensional step-scheme heterojunctions were synthesized through a controlled dehydroxylation process of indium-based precursors.The charge trans-fer mechanism of this step-scheme heterojunctions was confirmed by the characterization of electron structures,reactive species,photoelectric properties and DFT theoretical calculation.The band bending and the internal electric field caused by the charge transfer upon hybridization can effectively promote the separation of charges and present the optimal redox capacity,In addition,surface residual hydroxyl groups can regulate the surface energy state and optimize the interfacial charge transfer kinetics of the prepared step-scheme heterojunction.Eventually,the step-scheme heterojunction exhibits superior performance in photocatalytic reduction of hexavalent chromium and degradation of organic pollutants under visible light irradiation.This work provides an innovative perspective to construct photocatalyst with superior activity.