Flexible Molecular Precursors for Selective Decomposition to Nickel Sulfide or Nickel Phosphide for Water Splitting and Supercapacitance.

Autor: Ayom GE; Department of Chemistry, University of Zululand, Private bag X1001, Kwa-Dlangezwa, 3880, South Africa., Khan MD; Department of Chemistry, University of Zululand, Private bag X1001, Kwa-Dlangezwa, 3880, South Africa., Ingsel T; Department of Chemistry, Pittsburg State University, Pittsburg, 66762, Kansas, USA., Lin W; Department of Chemistry, Pittsburg State University, Pittsburg, 66762, Kansas, USA., Gupta RK; Department of Chemistry, Pittsburg State University, Pittsburg, 66762, Kansas, USA., Zamisa SJ; School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X54001, Westville Campus, Durban, 4000, South Africa., van Zyl WE; School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X54001, Westville Campus, Durban, 4000, South Africa., Revaprasadu N; Department of Chemistry, University of Zululand, Private bag X1001, Kwa-Dlangezwa, 3880, South Africa.
Jazyk: angličtina
Zdroj: Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2020 Feb 26; Vol. 26 (12), pp. 2693-2704. Date of Electronic Publication: 2020 Feb 21.
DOI: 10.1002/chem.201904583
Abstrakt: Herein, the synthesis of three nickel(II) dithiophosphonate complexes of the type [Ni{S 2 P(OR)(4-C 6 H 4 OMe)} 2 ] [R=H (1), C 3 H 7 (2)] and [Ni{S 2 P(OR)(4-C 6 H 4 OEt} 2 ] [R=(C 6 H 5 ) 2 CH (3)] is described; their structures were confirmed by single-crystal X-ray studies. These complexes were subjected to surfactant/solvent reactions at 300 °C for one hour as flexible molecular precursors to prepare either nickel sulfide or nickel phosphide particles. The decomposition of complex 2 in tri-octylphosphine oxide/1-octadecene (TOPO/ODE), TOPO/tri-n-octylphosphine (TOP), hexadecylamine (HDA)/TOP, and HDA/ODE yielded hexagonal NiS, Ni 2 P, Ni 5 P 4 , and rhombohedral NiS, respectively. Similarly, the decomposition of complex 1 in TOPO/TOP and HDA/TOP yielded hexagonal Ni 2 P and Ni 5 P 4 , respectively, and that of complex 3 in similar solvents led to hexagonal Ni 5 P 4 , with TOP as the likely phosphorus provider. Hexagonal NiS was prepared from the solvent-less decomposition of complexes 1 and 2 at 400 °C. NiS (rhom) had the best specific supercapacitance of 2304 F g -1 at a scan rate of 2 mV s -1 followed by 1672 F g -1 of Ni 2 P (hex). Similarly, NiS (rhom) and Ni 2 P (hex) showed the highest power and energy densities of 7.4 kW kg -1 and 54.16 W kg -1 as well as 6.3 kW kg -1 and 44.7 W kg -1 , respectively. Ni 5 P 4 (hex) had the lowest recorded overpotential of 350 mV at a current density of 50 mA cm -2 among the samples tested for the oxygen evolution reaction (OER). NiS (hex) and Ni 5 P 4 (hex) had the lowest overpotentials of 231 and 235 mV to achieve a current density of 50 mA cm -2 , respectively, in hydrogen evolution reaction (HER) examinations.
(© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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