Porous AgCl/Ag nanocomposites were fabricated with a facile two-step route, which involves the formation of nanoporous silver (NPS) by dealloying AgAl alloys, and a subsequent surface chlorination in a mixed solution containing H2O2 and HCl. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and UV−vis spectroscopy were used to characterize the resulting samples, which revealed a porous AgCl/Ag composite nanostructure that inherited the bicontinuous spongy morphology of NPS precursors with interconnected pore channels and solid ligaments. The existence of Ag in the structure was found to contribute greatly to enhanced absorption in the visible light region. In a test system for the degradation of methylic orange (MO) dye, it was found that porous AgCl/Ag nanocomposites performed very well as efficient and stable visible light catalysts. Under nonoptimized conditions, the MO dye degradation rate can reach as high as 0.75 mg/min·gcat with 420 nm irrad...