Herein, the synthesis of three nickel(II) dithiophosphonate complexes of the type [Ni{S2P(OR)(4‐C6H4OMe)}2] [R=H (1), C3H7 (2)] and [Ni{S2P(OR)(4‐C6H4OEt}2] [R=(C6H5)2CH (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, Ni2P, Ni5P4, and rhombohedral NiS, respectively. Similarly, the decomposition of complex 1 in TOPO/TOP and HDA/TOP yielded hexagonal Ni2P and Ni5P4, respectively, and that of complex 3 in similar solvents led to hexagonal Ni5P4, 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 Ni2P (hex). Similarly, NiS (rhom) and Ni2P (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. Ni5P4 (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 Ni5P4 (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.

Straightforward synthetic routes to the preparation of transition metal phosphides or their chalcogenide analogues are highly desired due to their widespread applications, including catalysis. We report a facile and simple route for the preparation of a pure phase nickel phosphide (Ni 2 P) and phase transformations in the nickel sulfide (NiS) system through a solvent-less synthetic protocol. Decomposition of different sulfur-based complexes (dithiocarbamate, xanthate, and dithiophosphonate) of nickel(II) was investigated in the presence and absence of triphenylphosphine (TPP). The optimization of reaction parameters (nature of precursor, ratio of TPP, temperature, and time) indicated that phosphorus-and sulfur-containing inorganic dithiophosphonate complexes and TPP (1:1 mole ratio) produced pure nickel phosphide, whereas different phases of nickel sulfide were obtained from dithiocarbamate and xanthate precursors in the presence or absence of TPP. A plausible explanation of the sulfide or phosphide phase formation is suggested, and the performance of Ni 2 P was investigated as an electrocatalyst for supercapacitance and overall water-splitting reactions. The performance of Ni 2 P with the surface free of any capping agents is not well explored, as common synthetic methods are solution-based routes; therefore, the electrocatalytic performance was also compared with metal phosphides, prepared by other routes. The highest specific capacitance of 367 F/g was observed at 1 A/g, and the maximum energy and power density of Ni 2 P were calculated to be 17.9 Wh/kg and 6951 W/kg, respectively. The prepared nickel phosphide required overpotentials of 174 and 316 mV along with Tafel slopes of 115 and 95 mV/dec to achieve a current density of 10 mA/cm 2 for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), respectively.

Cost-effective and readily available catalysts applicable for electrochemical conversion technologies are highly desired. Herein, we report the synthesis of dithiophosphonate complexes of the type [Ni{S2P(OH)(4-CH3OC6H4)}2] (1), [Co{S2P(OC4H9)(4-CH3OC6H4)}3] (2) and [Fe{S2P(OH)(4-CH3OC6H4)}3]...

The synthesis of pure-phase nickel phosphide is of immense interest due to its wide scale applications in various electrocatalytic reactions. We report the facile synthesis of nickel phosphides and rare...

C20H30Cl6CoN2, orthorhombic, Pbca (no. 61), a = 20.756(1) Å, b = 9.3427(5) Å, c = 27.6827(12) Å, V = 5368.1(5) Å3, Z = 8, Rgt(F) = 0.0235, wRref(F2) = 0.0593, T = 100(2) K.