Designing a Phenalenyl-Based Dinuclear Ni(II) Complex: An Electrocatalyst with Two Single Ni Sites for the Oxygen Evolution Reaction (OER)

A new dinuclear Ni(II) complex 1, [Ni2II(dtbh-PLY)2], is synthesized from 9-(2-(3,6-di-tert-butyl-2-hydroxybenzylidene)hydrazineyl)-1H-phenalen-1-one, dtbh-PLYH2 ligand, and structurally characterized by various analytical tools including the single-crystal X-ray diffraction (SCXRD) technique. In the solid state, both Ni(II) metal centers in complex 1 exist in a distorted square planar geometry and display the presence of rare Ni···H-C anagostic interactions to form a one-dimensional (1-D) linear motif in the supramolecular array. Complex 1 is further stabilized in the solid state by π-π-stacking interactions between the highly delocalized phenalenyl rings. The redox features of complex 1 have been analyzed by the cyclic voltammetry (CV) technique in solution as well as in the solid state, revealing the crucial involvement of both the Ni(II) metal centers for undergoing quasi-reversible oxidation reactions on the application of an anodic sweep. A complex 1-modified glassy carbon electrode, GC-1, is employed as an electrocatalyst for oxygen evolution reaction (OER) in 1.0 M KOH, giving an OER onset at 1.45 V, and very low OER overpotential, 300 mV vs the reversible hydrogen electrode (RHE) to reach 10 mA cm-2 current density. Furthermore, GC-1 displayed fast OER kinetics with a Tafel slope of 40 mV dec-1, a significantly lower Tafel slope value than those of previously reported molecular Ni(II) catalysts. In situ electrochemical experiments and postoperational UV-vis, Fourier transform infrared (FT-IR), scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) studies were performed to analyze the stability of the molecular nature of complex 1 and to gain reasonable insights into the true OER catalyst.

Triphasic Ni2 P-Ni12 P5 -Ru with Amorphous Interface Engineering Promoted by Co Nano-Surface for Efficient Water Splitting

This research designs a triphasic Ni2 P-Ni12 P5 -Ru heterostructure with amorphous interface engineering strongly coupled by a cobalt nano-surface (Co@Nim Pn -Ru) to form a hierarchical 3D interconnected architecture. The Co@Nim Pn -Ru material promotes unique reactivities toward hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media. The material delivers an overpotential of 30 mV for HER at 10 mA cm-2 and 320 mV for OER at 50 mA cm-2 in freshwater. The electrolyzer cell derived from Co@Nim Pn -Ru(+,-) requires a small cell voltage of only 1.43 V in alkaline freshwater or 1.44 V in natural seawater to produce 10 mA cm-2 at a working temperature of 80 °C, along with high performance retention after 76 h. The solar energy-powered electrolyzer system also shows a prospective solar-to-hydrogen conversion efficiency and sufficient durability, confirming its good potential for economic and sustainable hydrogen production. The results are ascribed to the synergistic effects by an exclusive combination of multi-phasic crystalline Ni2 P, Ni12 P5 , and Ru clusters in presence of amorphous phosphate interface attached onto cobalt nano-surface, thereby producing rich exposed active sites with optimized free energy and multi open channels for rapid charge transfer and ion diffusion to promote the reaction kinetics.

Two bis-ligand-coordinated Zn(ii)-MOFs for luminescent sensing of ions, antibiotics and pesticides in aqueous solutions

Two organometallic complexes with two and three-dimensional architectures were constructed by using multiple ligands and Zn(ii) ions: [Zn₃(BTC)₂(DTP)₄(H₂O)₂]·(H₂O)₄ (Zn-1) (BTC = benzene-1,3,5-tricarboxylic acid and DTP = 3,5-di(1,2,4-triazol-1-yl)pyridine) and [Zn₂(NTD)₂(DTP)] (Zn-2) (NTD = 1,4-naphthalenedicarboxylic acid). The as-prepared complexes were characterized by single-crystal X-ray diffraction (SCXRD), elemental analysis, powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and fluorescence analysis. Fluorescence sensing tests revealed that the two complexes are effective, sensitive and selective toward cationic Fe³⁺ and anionic MnO₄ ^- and Cr₂O₇ ^2-. During the antibiotic sensing process, cefixime (CFX) for Zn-1 and nitrofurantoin (NFT) for Zn-2 exhibited the highest quenching efficiencies. For sensing pesticides, the highest quenching efficiencies were exhibited by imidacloprid (IMI) toward Zn-1 and Zn-2. The fluorescence quenching of the complexes that was induced by antibiotics, pesticides and MnO₄ ^- was attributed to both the inner filter effect (IFE) and the fluorescence resonance energy transfer (FRET) effect.

Experimental and theoretical investigation of the tuning of electronic structure in SnO2via Co doping for enhanced styrene epoxidation catalysis

Co doping is an effective strategy for the tuning of electronic structure in SnO2, which leads to a huge boost in the styrene epoxidation reaction performance.

Concerted effect of Ni-in and S-out on ReS2 nanostructures towards high-efficiency oxygen evolution reaction

Herein, a one-step hydrothermal reaction is developed to synthesize Ni-doped ReS2 nanostructure with the sulphur defect. The material exhibited excellent OER activity with a current density of 10 mAcm-2 at...

Synthesis, structure, and fluorescence properties of coordination polymers of 3,5-bis(1′,2′,4′-triazol-1′-yl) pyridine

Four coordination polymers based on 3,5-bis(1′,2′,4′-triazol-1′-yl) pyridine were synthesized. Compounds [Cd₃(btc)₂(btap)(H₂O)₆] and [Cd(oa)(btap)] exhibited high sensitivity luminescence response towards Fe³⁺, Ce³⁺, Cr₂O₇²⁻ and MnO₄⁻ in aqueous solution.

Structural diversity and photocatalytic activity of six Co(ii)/Ni(ii) complexes with three flexible phenylenediacetate isomers

Six coordination polymers show structural diversity have been reported. Their photocatalytic for the degradation of dye have been well studied.

Two-dimensional bimetallic CoFe selenite via metal-ion assisted self-assembly for enhanced oxygen evolution reaction

A 2D CoFe selenite crystals was used as an efficient OER catalyst, which was obtained in a high yield via a simple metal-ion self-assembly strategy under hydrothermal condition.

Synthesis, structure, and photoluminescence properties of coordination polymers of 4,4′,4′′,4′′′-tetrakiscarboxyphenylsilane and 3,5-bis(1′,2′,4′-triazol-1′-yl)pyridine

Three coordination polymers based on 4,4′,4′′,4′′′-tetrakiscarboxyphenylsilane and 3,5-bis(1′,2′,4′-triazol-1′-yl)pyridine ligands were synthesized. Luminescence studies revealed that [Cd₃(Htcps)₂(btap)(H₂O)₆] exhibits a luminescence quenching response towards Fe³⁺ and Cu²⁺.

Trinuclear Ni(ii) oriented highly dense packing and π-conjugation degree of metal–organic frameworks for efficient water oxidation

Trinuclear nickel cluster based MOF shows highly denser crystal packing and π-conjugation degree as well as outstanding OER performance with an overpotential of 270 mV at 10 mA cm⁻².