In the present paper, we report the synthesis of activated carbon supported strontium/cerium bimetallic nanocomposite (Sr/Ce/AC BNC) that has been prepared by simple microwave reduction method. X-Ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), X-Ray diffraction (XRD) and Transmission electron microscopy (TEM) analyses were performed to characterize the fabricated Sr/Ce/AC BNC. Sr/Ce/AC BNC has been found to be efficient photocatalyst and has been explored for the degradation of rhodamine B under natural sunlight irradiation. The photocatalytic activity of Sr/Ce/AC was evaluated based on reaction kinetics to remove rhodamine B, chemical oxygen demand (COD), and total organic content (TOC). Hydroxyl radicals have been found to be the active participating species which was confirmed by using appropriate radical scavengers. Degradation intermediate products of rhodamine B has been identified using LC-MS and the reaction pathways were proposed and discussed in the manuscript. In short, this work provides a deep insight into the utilization of Sr/Ce/AC BNC as effective photocatalyst.