The nanoporous copper (Cu) powders (NPCPs) co-existing with Cu2O was fabricated by dealloying of atomized Zr-Cu-Ni-Al amorphous powders. The as-fabricated NPCPs, with an inner core and outer shell, showed a large specific surface area of 7.52 m(2) g(-1) and exhibited significantly superior degradation ability in the presence of hydrogen peroxide (H2O2) for the complete elimination of methyl orange (MO) under both acidic and neutral environments. The enhanced catalytic decomposition properties of H2O2 by NPCPs were mainly attributed to the large specific surface area and three-dimensional continuous nanoporous structure with unique atomic steps on the ligament surfaces. The mechanistic investigations revealed that Cu2O/H2O2 reactions in acidic environment and Cu/H2O2 reactions in neutral environment, respectively, were responsible for the high degradability of azo dyes, indicating that NPCPs/H2O2 could be a good Fenton-like reagent in application of wastewater treatments. (C) 2017 Elsevier B.V. All rights reserved.