Fabrication and new electrochemical properties of nanoporous Cu by dealloying amorphous Cu–Hf–Al alloys

•NPC ribbons with good mechanical integrity and bendability are fabricated.•Amorphous alloy-containing interlayer is designed to improve bendability of NPC.•3D NPC improves specific capacitance of MnO2 by transforming shape.•NPC is revealed in a potential application for supercapacitor composite electrodes.

To produce monolithic nanoporous Cu (NPC) ribbons with good mechanical integrity, we investigate chemical dealloying behavior of an amorphous Cu52.5Hf40Al7.5 alloy with good mechanical properties by immersion in 0.5 M HF solution for different times. With the design concept of adding ductile amorphous supporter to NPC ribbons, an amorphous alloy-containing interlayer with a certain thickness is successfully fabricated in the NPC ribbon by controlling dealloying time to ensure the good bendability of the dealloyed product. New electrochemical properties of the obtained NPC ribbon are further developed. The current signal and the specific capacitance of the NPC-supported MnO2 composite electrode are remarkably enhanced as compared to those of pure MnO2 powders. NPC substrate with large specific surface areas and excellent electrical conductivity can effectively promote the morphological change of MnO2 from globular particles to nanoflakes for larger specific surface area and improve the utilization of MnO2 surface active sites, which reveal new electrochemical properties of NPC in a potential application for supercapacitor composite electrodes.