Unprotected and interconnected Ru0 nano-chain networks: advantages of unprotected surfaces in catalysis and electrocatalysis

Core-shell CoFe2O4@Co-Fe-Bi nanoarray: a surface-amorphization water oxidation catalyst operating at near-neutral pH

The exploration of high-performance and earth-abundant water oxidation catalysts operating under mild conditions is highly attractive and challenging. In this communication, core-shell CoFe₂O₄@Co-Fe-Bi nanoarray on carbon cloth (CoFe₂O₄@Co-Fe-Bi/CC) was successfully fabricated by in situ surface amorphization of CoFe₂O₄ nanoarray on CC (CoFe₂O₄/CC). As a 3D water oxidation electrode, CoFe₂O₄@Co-Fe-Bi/CC shows outstanding activity with an overpotential of 460 mV to drive a geometrical catalytic current density of 10 mA cm^-2 in 0.1 M potassium borate (pH 9.2). Notably, it also demonstrates superior long-term durability for at least 20 h with 96% Faradic efficiency. Density functional theory calculations indicate that the conversion from OOH* to O₂ is the rate-limiting step and the high water oxidation activity of CoFe₂O₄@Co-Fe-Bi/CC is associated with the lower free energy of 1.84 eV on a Co-Fe-Bi shell.

Microwave-Initiated Facile Formation of Ni3Se4 Nanoassemblies for Enhanced and Stable Water Splitting in Neutral and Alkaline Media

Molecular hydrogen (H₂) generation through water splitting with minimum energy loss has become practically possible due to the recent evolution of high-performance electrocatalysts. In this study, we fabricated, evaluated, and presented such a high-performance catalyst which is the Ni₃Se₄ nanoassemblies that can efficiently catalyze water splitting in neutral and alkaline media. A hierarchical nanoassembly of Ni₃Se₄ was fabricated by functionalizing the surface-cleaned Ni foam using NaHSe solution as the Se source with the assistance of microwave irradiation (300 W) for 3 min followed by 5 h of aging at room temperature (RT). The fabricated Ni₃Se₄ nanoassemblies were subjected to catalyze water electrolysis in neutral and alkaline media. For a defined current density of 50 mA cm^-2, the Ni₃Se₄ nanoassemblies required very low overpotentials for the oxygen evolution reaction (OER), viz., 232, 244, and 321 mV at pH 14.5, 14.0, and 13.0 respectively. The associated lower Tafel slope values (33, 30, and 40 mV dec^-1) indicate the faster OER kinetics on Ni₃Se₄ surfaces in alkaline media. Similarly, in the hydrogen evolution reaction (HER), for a defined current density of 50 mA cm^-2, the Ni₃Se₄ nanoassemblies required low overpotentials of 211, 206, and 220 mV at pH 14.5, 14.0, and 13.0 respectively. The Tafel slopes for HER at pH 14.5, 14.0, and 13.0 are 165, 156, and 128 mV dec^-1, respectively. A comparative study on both OER and HER was carried out with the state-of-the-art RuO₂ and Pt under identical experimental conditions, the results of which revealed that our Ni₃Se₄ is a far better high-performance catalyst for water splitting. Besides, the efficiency of Ni₃Se₄ nanoassemblies in catalyzing water splitting in neutral solution was carried out, and the results are better than many previous reports. With these amazing advantages in fabrication method and in catalyzing water splitting at various pH, the Ni₃Se₄ nanoassemblies can be an efficient, cheaper, nonprecious, and high-performance electrode for water electrolysis with low overpotentials.

A nickel–borate–phosphate nanoarray for efficient and durable water oxidation under benign conditions

A nickel–borate–phosphate nanoarray (Ni–Bi–Pi/CC) topotactically converted from a nickel phosphide nanoarray (Ni₂P/CC) acts as a durable catalyst electrode for water oxidation needing an overpotential of 440 mV to drive 10 mA cm⁻² in 0.1 M K–Bi (pH: 9.2).

Magnetic CoPt nanoparticle-decorated ultrathin Co(OH)2 nanosheets: an efficient bi-functional water splitting catalyst

Magnetic CoPt bimetallic NPs anchored on ultrathin Co(OH)₂ nanosheet arrays functioned as an efficient bi-functional water splitting catalyst where the intrinsic magnetism of CoPt was used to improve the stability further by providing external magnetic support.

Iron hydroxyphosphate and Sn-incorporated iron hydroxyphosphate: efficient and stable electrocatalysts for oxygen evolution reaction

New, iron-based, nanocrystals of Fe₅(PO₄)₄(OH)₃·2H₂O and Sn-incorporated Fe₅(PO₄)₄(OH)₃·2H₂O were synthesized and their electrocatalytic OERs were enhanced because of the presence of PO₄³⁻ ligands and the Sn incorporation.

Petal-like hierarchical array of ultrathin Ni(OH)2 nanosheets decorated with Ni(OH)2 nanoburls: a highly efficient OER electrocatalyst

A solvothermally synthesized petal-like 3D hierarchical array of β-Ni(OH)₂ nanosheets and nanoburls has displayed an abnormal enhancement in activity in the OER as a consequence of surface faceting of planes from (001) to (101) and (202) within a minimum number of potential sweeps in addition to the formation of oxyhydroxide.

Ruthenium nanoparticles supported over mesoporous TiO2 as an efficient bifunctional nanocatalyst for esterification of biomass-derived levulinic acid and transfer-hydrogenation reactions

Ru NPs supported over mesoporous TiO₂ nanocatalyst and its catalytic activity was evaluated in the esterification of levulinic acid and selective transfer hydrogenation of nitroarenes.

Shape-selective synthesis of Sn(MoO4)2 nanomaterials for catalysis and supercapacitor applications

Size and shape-selective Sn(MoO₄)₂ nanomaterials were synthesized for the first time using hydrothermal route. Needle-like and flake-like nanomaterials were used for two applications, the photocatalytic reduction of nitroarenes and in electrochemical supercapacitors.