title: Synthesis of Nickel Phosphide Electrocatalysts from Hybrid Metal Phosphonates.
abstract: Transition-metal phosphides (TMPs) have recently emerged as efficient and inexpensive electrocatalysts for electrochemical water splitting. The synthesis of nanostructured phosphides often involves highly reactive and hazardous phosphorous-containing compounds. Herein, we report the synthesis of nickel phosphides through thermal treatment under H2(5%)/Ar of layered nickel phenylphosphonate (NiPh) or methylphosphonate (NiMe) that act as single-source precursors. Ni12P5, Ni12P5-Ni2P, and Ni2P nanoparticles (NPs) with sizes of ca. 15-45 nm coated with a thin shell of carbonaceous material were produced. Thermogravimetric analysis coupled with mass spectrometry (TG-MS) showed that H2, H2O, P2, and -C6H5are the main compounds formed during the transformation of the precursor under argon and no hazard phosphorous-containing compounds are created, making this a simple and relatively safe route for fabricating nanostructured TMPs. The H2most likely reacts with the -PO3groups of the precursor to form H2O and P2, and the latter subsequently reacts with the metal to produce the phosphide. The Ni12P5-Ni2P and Ni2P NPs efficiently catalyze the hydrogen evolution reaction (HER), with Ni2P showing the best performance and generating a current density of 10 mA cm-2at an overpotential of 87 mV and exhibiting long-term stability. Co2P and CoP NPs were also synthesized following this method. This approach may be utilized to explore the rich metal phosphonate chemistry for fabricating phosphide-based materials for electrochemical energy conversion and storage applications.
authors.affiliation: Institut für Chemie and IRIS Adlershof, Humboldt-Universität zu Berlin , Brook-Taylor-Str. 2, 12489 Berlin, Germany.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Institut für Chemie and IRIS Adlershof, Humboldt-Universität zu Berlin , Brook-Taylor-Str. 2, 12489 Berlin, Germany.
authors.forename: Patrícia A
authors.initials: PA
authors.lastname: Russo
authors.affiliation: Institut für Chemie and IRIS Adlershof, Humboldt-Universität zu Berlin , Brook-Taylor-Str. 2, 12489 Berlin, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Feist
authors.affiliation: Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin , Brook-Taylor-Str. 6, 12489 Berlin, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Amsalem
authors.affiliation: Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin , Brook-Taylor-Str. 6, 12489 Berlin, Germany.
authors.forename: Norbert
authors.identifier: http://orcid.org/0000-0002-6042-6447
authors.initials: N
authors.lastname: Koch
authors.affiliation: Institut für Chemie and IRIS Adlershof, Humboldt-Universität zu Berlin , Brook-Taylor-Str. 2, 12489 Berlin, Germany.
authors.forename: Nicola
authors.identifier: http://orcid.org/0000-0003-1273-803X
authors.initials: N
authors.lastname: Pinna
keywords: Hydrogen evolution reaction; cobalt phosphide; nickel phosphide; oxygen evolution reaction; transition-metal phosphide; transition-metal phosphonate