The sluggish kinetics of both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) generate the large overpotential in water electrolysis and thus high-cost hydrogen production. Here, multidimensional nanoporous interpenetrating-phase FeNiZn alloy and FeNi₃ intermetallic heterostructure is in situ constructed on NiFe foam (FeNiZn/FeNi₃@NiFe) by dealloying protocol. Coupling with the eminent synergism among specific constituents and the highly efficient mass transport from integrated porous backbone, FeNiZn/FeNi₃@NiFe depicts exceptional bifunctional activities for water splitting with extremely low overpotentials toward OER and HER (η₁₀₀₀ = 367/245 mV) as well as the robust durability during the 400 h testing in alkaline solution. The as-built water electrolyzer with FeNiZn/FeNi₃@NiFe as both anode and cathode exhibits record-high performances for sustainable hydrogen output in terms of much lower cell voltage of 1.759 and 1.919 V to deliver the current density of 500 and 1000 mA cm⁻² as well long working lives. Density functional theory calculations disclose that the interface interaction between FeNiZn alloy and FeNi₃ intermetallic generates the modulated electron structure state and optimized intermediate chemisorption, thus diminishing the energy barriers for hydrogen production in water splitting. With the merits of fine performances, scalable fabrication, and low cost, FeNiZn/FeNi₃@NiFe holds prospective application potential as the bifunctional electrocatalyst for water splitting."Image missing"

We describe the simple preparation of octahedral Mn₃O₄ nanomaterials with a typical diameter around 300–400 nm using a one step dealloying of MnAl alloy at room temperature. The as-made sample exhibits high performance as an anode material for Li-ion batteries. Electrochemical measurements reveal that the Mn₃O₄ octahedra have an ultralong cycle life with capacity retentions of 81.3% and 77.8% after 500 cycles at 100 and 300 mA g⁻¹, respectively. Moreover, the Mn₃O₄ octahedra deliver a stable capacity at a high rate of 1000 mA g⁻¹ with a good rate capability. The as-made Mn₃O₄ octahedra exhibit great potential for application as anode materials for Li-ion batteries with the advantages of unique performance and easy preparation.