Tremendous demands for renewable hydrogen generated from water splitting have stimulated intensive research on developing earth-abundant, non-noble, and versatile metal catalysts toward the hydrogen evolution reactions (HER). Here, self-supported Cu-Ni-Al hybrid electrodes that are composed of electroactive Al 7 Cu 4 Ni@Cu 4 Ni core/shell nanocrystals seamlessly integrated in selfsupported 3D bimodal nanoporous Cu skeleton (Bi-NP Cu/Al 7 Cu 4 Ni@Cu 4 Ni) as robust HER electrocatalysts in alkaline electrolyte are reported. As a result of the proper architecture, in which the Bi-NP Cu skeleton not only facilitates both electron and electrolyte transports but also provides high specific surface areas to fully use high electrocatalytic activity of Al 7 Cu 4 Ni@Cu 4 Ni core/shell nanocrystals, the Bi-NP Cu/Al 7 Cu 4 Ni@Cu 4 Ni hybrid catalysts exhibit a low onset overpotential of 60 mV and a small Tafel slope of 110 mV dec −1 , enabling the catalytic current density of 10 mA cm −2 at a low overpotential of 139 mV. The highly stable electrochemical performance makes them promising candidates as cathode catalysts in alkaline-based devices.

Chromium-doped NiFe oxyhydroxide nanosheets that are quasi-vertically oriented on three-dimensional nanoporous gold exhibit superior catalytic activity towards the oxygen evolution reaction.