The development of effective electrocatalysts for sustainable energy conversion and storage is highly desired, but still a considerable challenge due to the sluggish oxygen evolution reaction (OER). Herein, we report...

and so on. Among them, Ni-based materials, especially Ni 3 S 2 , have been extensively studied for use as an effective OER catalyst owing to its inherent advantages of good conductivity and unique 3D configuration. However, widespread use of Ni 3 S 2 electrocatalysts is still severely restricted by their low surface area exposure and poor electrocatalytic stability. [24,25] To overcome the above issues, it is vital to design efficient strategies to optimize the catalytic performances of the electrocatalysts. Most recently, Prussian blue analogs (PBAs) have been intensively employed for the applications in electrocatalysis, batteries and supercapacitors. [26][27][28] PBAs are considered as a promising class of materials because of 1) the 3D open framework with large interstitial sites; 2) the open, low strain, and tunable skeleton; 3) their adjustable composition, good structure, and chemical stability; and 4) their special thermal properties and unique reactivity. [26][27][28] When PBAs are applied for electrocatalysis, the porous PBA-derived materials with open diffusion channels, well-defined structure, and large surface area could be synthesized by taking PBAs as templates or precursors, such as transition metal sulfides, [29][30][31][32] selenides, [33] phosphides, [34,35] nitrides, [36] and oxides. [37] The specific structure of these porous PBA-derived materials is essential in providing rapid electron and electrolyte transportation pathway and improving the electrochemical properties.However, porous iron-nickel sulfide nanosheets derived from nickel-iron PBA (NiFe PBA) and nickel hydroxide have never been reported. Therefore, a simple and convenient approach should be developed to fabricate porous ironnickel sulfide nanosheets based on PBA. Inspired by these points, we successfully synthesized an interpenetrated porous 3D-networked FeS-Ni 3 S 2 on nickel foam (NF) through partial chemical etching of Ni(OH) 2 /NF nanosheets with Fe(CN) 6 3− to obtain Ni(OH) 2 @NiFe PBA/NF nanoarrays and subsequently treated with chemical etching/anion exchanging of Fe(CN) 6 3− and OH − by S 2− . [30,32,34] Benefiting from the unique interpenetrated porous 3D-networked architecture, the obtained metal sulfide electrode would expose large edge active sites and possess high-speed charge/mass transfer and relatively high electrochemical active area, resulting in the boosted electrocatalytic activities and durability for OER. [38] As a result, it delivers much The development of high-efficient and cost-effective catalytic electrodes for oxygen evolution reaction (OER) is highly desirable. Herein, interpenetrated porous 3D-networked iron-nickel sulfide nanosheets are synthesized on nickel foam (NF) (donated as FeS-Ni 3 S 2 /NF) via partial chemical etching of Ni(OH) 2 /NF precursor with Fe(CN) 6 3− , followed by chemical etching/anion exchanging of Fe(CN) 6 3− and OH − with S 2− . The resulting FeS-Ni 3 S 2 /NF nanosheets possess a remarkable catalytic activity for the OER with overpotentials of only 238 and 290 mV at 10 and 100 ...

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A novel La 2 NiO 4 photocatalyst in layered perovskite crystal was synthesized by co-alcoholysis of La(NO 3 ) 3 and Ni(NO 3 ) 2 under solvothermal conditions. It exhibited high activity for mineralizing 4-chlorophenol under visible light irradiation and even in the dark, leading to round-the-clock photocatalysis. The photocatalytic mechanism of the La 2 NiO 4 in the absence of light irradiation was discussed based on both the structural characterizations and the kinetic studies. Both the La 2 NiO 4 crystals and the organic molecules played key roles for starting the degradation reaction in dark. The 4-chlorophenol firstly ionized into anions, followed by donating electrons to La 2 NiO 4 owing to the positively charged surface. Then, the electrons could react with dissolved O 2 to produce ? O 2 2 , which subsequently reacted with H + to form ? OH radicals. These highly active ? OH radicals could oxidize 4-chlorophenol into CO 2 , leading to complete degradation.

A novel Ni–S/MIL-53(Fe) catalyst fabricated via electrodepositing sulfur-engineered amorphous nickel hydroxides on MIL-53(Fe) nanosheets has been used as a highly efficient electrocatalyst for the OER.