Water splitting is widely considered to be a promising strategy for clean and efficient energy production. In this paper, for the first time we report an in situ growth of iron− nickel nitride nanostructures on surface-redox-etching Ni foam (FeNi 3 N/NF) as a bifunctional electrocatalyst for overall water splitting. This method does not require a specially added nickel precursor nor an oxidizing agent, but achieves well-dispersed iron−nickel nitride nanostructures that are grown directly on the nickel foam surface. The commercial Ni foam in this work not only acts as a substrate but also serves as a slow-releasing nickel precursor that is induced by redox-etching of Fe 3+ . FeCl 2 is a more preferable iron precursor than FeCl 3 for no matter quality of FeNi 3 N growth or its electrocatalytic behaviors. The obtained FeNi 3 N/NF exhibits extraordinarily high activities for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) with low overpotentials of 202 and 75 mV at 10 mA cm −2 , Tafel slopes of 40 and 98 mV dec −1 , respectively. In addition, the presented FeNi 3 N/NF catalyst has an extremely good durability, reflecting in more than 400 h of consistent galvanostatic electrolysis without any visible voltage elevation.

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Bowl-like hybrid structures constructed by anchoring NiO nanosheets on flat carbon shells exhibit superior lithium storage properties.

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Fundamental understanding of constructing elevated catalysts to realize fast electron transfer and rapid mass transport in oxygen reduction reaction (ORR) chemistry by interface regulation and structure design is important but still ambiguous. Herein, a novel jellyfish-like Mott-Schottkytype electrocatalyst is developed to realize fast electron transfer and decipher the structure-mass transport connection during ORR process. Both spectroscopy techniques and density functional theory calculation demonstrate electrons spontaneously transfer from Fe to N-doped graphited carbon at the heterojunction interface, thus accelerating electron transfer from electrode to reactant. Dynamic analysis indicates unique structure can significantly improve mass transport of oxygen-species due to two factors: one is electrolyte streaming effect caused by tentacle-like carbon nanotubes; the other is effective collision probability in the semiclosed cavity. Therefore, this Mott-Schottky-type catalyst delievers superior ORR performance with high onset potential, positive half wave potential, and large current density. It also exhibits low overpotential when serving as an air cathode in Zn-air batteries. This work deepens understanding of the two key factors-electron transfer and mass transport-on determining the kinetic reaction of ORR process and offers a new avenue in constructing efficient Mott-Schottky electrocatalysts.