Perception of surface plasmonic resonance in heterogeneous photocatalysis not only has impact on basic science of sustainable energy development, but also generates green technologies for wastewater treatment, selective oxidation and reduction reactions. In the present study Au/Pd bimetallic alloyed nanoparticles were effectively decorated on mesoporous silica modified g-C3N4 (graphitic carbon nitride) nanosheets by a simple one-pot calcinations strategy. The formation of Au/Pd alloyed nanoparticles has been supported by XRD, UV-vis DRS, TEM and XPS studies. The photocatalytic performance of the photocatalysts were investigated by performing tandem reaction for simultaneous oxidation of phenol and reduction of Cr (VI). The photocatalytic performances were found to be significant for either single phenol species or single Cr (VI), but quite appreciable photocatalytic performance was observed for a solution containing Cr (VI)-phenol mixture. The synergetic effect of Au/Pd alloyed nanoparticle and enhanced photocurrent (1.4 mA/cm(2)) generated by the nano-composite further supports the activity. The results of tandem reaction not only reveals the feasibility of carrying out degradation of two important pollutants simultaneously from waste water, but also gives us an enlightenment to efficiently degrade mixture of pollutants without using any additional chemical as trapping agent in the photocatalytic process. (C) 2019 Published by Elsevier Inc.