Spherical Ni₃S₂/Fe‐NiP_x Magic Cube with Ultrahigh Water/Seawater Oxidation Efficiency

Abstract

The rational construction of earth‐abundant and advanced electrocatalysts for oxygen evolution reaction (OER) is extremely desired and significant to seawater electrolysis. Herein, by directly etching Ni3S2 nanosheets through potassium ferricyanide, a novel self‐sacrificing template strategy is proposed to realize the in situ growth of NiFe‐based Prussian blue analogs (NiFe PBA) on Ni3S2 in an interfacial redox reaction. The well‐designed Ni3S2@NiFe PBA composite as precursor displays a unique spherical magic cube architecture composed of nanocubes, which even maintains after a phosphating treatment to obtain the derived Ni3S2/Fe‐NiPx on nickel foam. Specifically, in alkaline seawater, the Ni3S2/Fe‐NiPx as OER precatalyst marvelously realizes the ultralow overpotentials of 336 and 351 mV at large current densities of 500 and 1000 mA cm–2, respectively, with remarkable durability for over 225 h, outperforming most reported advanced OER electrocatalysts. Experimentally, a series of characterization results confirm the reconstruction behavior in the Ni3S2/Fe‐NiPx surface, leading to the in situ formation of Ni(OH)2/Ni(Fe)OOH with abundant oxygen vacancies and grain boundaries, which constructs the Ni3S2/Fe‐NiPx reconstruction system responsible for the remarkable OER catalytic activity. Theoretical calculation results further verify the enhanced OER activity for Ni3S2/Fe‐NiPx reconstruction system, and unveil that the Fe‐Ni2P/FeOOH as active origin contributes to the central OER activity.

Hollow Mo-doped NiSx nanoarrays decorated with NiFe layered double-hydroxides for efficient and stable overall water splitting

“…33 Besides, the satellite peaks (denoted as “Sat”) situated at 861.76 and 880.33 eV are observed, while the other peak at 855.79 eV belongs to the metal Ni (0) of nickel foam. 38 For the S 2p area of the Mo–NiS x /NF (Fig. 3d), the spectrum is fitted to three peak positions belonging to S 2p 3/2 (161.38 eV) and S 2p 1/2 (162.3 eV) for the Ni–S bond and S 2p 1/2 (163.55 eV) for the Mo–S bond, respectively.…”

Breaking the symmetry of single-atom catalysts enables an extremely low energy barrier and high stability for large-current-density water splitting

“…In addition, it exhibits some activity decay due to the pollutants in natural seawater (1 M KOH + seawater), including bacteria and microbes, as well as small particulates, both of which would poison the electrode. 31,32 In addition to the OER, the HER electrocatalytic activity of different samples was probed in alkaline solutions (1.0 M KOH). As shown in Fig.…”

“…In addition, it exhibits some activity decay due to the pollutants in natural seawater (1 M KOH + seawater), including bacteria and microbes, as well as small particulates, both of which would poison the electrode. 31,32…”

CuCo2S4@B,N-Doped Reduced Graphene Oxide Hybrid as a Bifunctional Electrocatalyst for Oxygen Reduction and Evolution Reactions

“…The increasing energy demands, depleted energy resources, and environmental hazards that arose due to the combustion of fossil fuels compelled us to develop renewable and sustainable energy technology. Regenerative fuel cells, 1 water electrolyzers, 2 , 3 and metal–air batteries 4 − 6 are the most promising renewable and environmentally benign alternative energy technologies. However, oxygen evolution reaction (OER) on the anode and oxygen reduction reaction (ORR) on the cathode are crucial and challenging issues for water electrolyzers and fuel cells.…”