Mesoporous Ternary Nitrides of Earth-Abundant Metals as Oxygen Evolution Electrocatalyst

As sustainable energy becomes a major concern for modern society, renewable and clean energy systems need highly active, stable, and low-cost catalysts for the oxygen evolution reaction (OER). Mesoporous materials offer an attractive route for generating efficient electrocatalysts with high mass transport capabilities. Herein, we report an efficient hard templating pathway to design and synthesize three-dimensional (3-D) mesoporous ternary nickel iron nitride (Ni3FeN). The as-synthesized electrocatalyst shows good OER performance in an alkaline solution with low overpotential (259 mV) and a small Tafel slope (54 mV dec(−1)), giving superior performance to IrO(2) and RuO(2) catalysts. The highly active contact area, the hierarchical porosity, and the synergistic effect of bimetal atoms contributed to the improved electrocatalytic performance toward OER. In a practical rechargeable Zn–air battery, mesoporous Ni(3)FeN is also shown to deliver a lower charging voltage and longer lifetime than RuO(2). This work opens up a new promising approach to synthesize active OER electrocatalysts for energy-related devices. [Image: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s40820-020-0412-8) contains supplementary material, which is available to authorized users

Nickel selenide supported on nickel foam as an efficient and durable non-precious electrocatalyst for the alkaline water electrolysis

Herein, we describe an in-situ hybridization of Nickel Selenide (Ni3Se2) with a Nickel Foam (NF) current collector as an efficient, ultra-durable electrode for the continuous alkaline water electrolysis. Earth abundant, cost effective, non-precious self-made Ni3Se2/NF electrode delivers an oxygen evolution reaction (OER) overpotential value of 315 mV at a current density of 100 mA cm−2 (versus a reversible hydrogen electrode) in aqueous electrolyte of 1 M KOH. On a static current density of 100 mA cm−2, Ni3Se2/NF electrode shows a good OER stability over 285 h with very small potential loss of 5.5% in alkaline electrolyte. Accordingly, the alkaline water electrolyzer constructed with Ni3Se2/NF (anode) and NiCo2S4/NF (cathode), it requires 1.58 V to deliver 10 mA cm−2 current density, with 500 h continuous operation in 1 M KOH. In addition, we demonstrate that the light-driven water splitting using solar panel, it can be a promising approach to facilitate true independence from electricity in H2 fuel economy. Overall, this methodology is one of the appropriate energy efficient ways to reduce the cost of water splitting devices, as it may simplify the diverse process and equipment. © 2016 Elsevier B.V.

Inexpensive electrochemical synthesis of nickel iron sulphides on nickel foam: super active and ultra-durable electrocatalysts for alkaline electrolyte membrane water electrolysis

Efficient and durable electrocatalysts for water splitting (both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER)) are required for the replacement of expensive noble metal-based catalysts used in water electrolysis devices. Herein, we describe the inexpensive synthesis of electrochemically deposited nickel iron sulphides on nickel foam (NiFeS/NF) and their use as highly efficient bi-functional water splitting catalysts that can meet the current energy demands. The NiFeS/NF electrocatalysts exhibited low overpotentials of approximately 231 mV for the OER and 180 mV for the HER in 1 M KOH. Moreover, the NiFeS/NF electrocatalysts exhibited a turnover frequency of one order of magnitude higher than those of state-of-the-art noble metal catalysts (RuO2 and Pt/C) for the OER and HER. In addition to this excellent activity, the bi-functional catalyst also exhibited an outstanding OER and HER electrode stability for over 200 h with minimal loss in activity. Further, it can be directly used in the practical application of alkaline electrolyte membrane water electrolysis. The high performance, prolonged electrode stability, and facile synthesis as an adherent coating on nickel foam suggest that NiFeS/NF electrocatalysts might be suitable for use as alternative commercially viable catalysts. © 2016 The Royal Society of Chemistry. This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence(CC-BY-NC)