Colloidal Ni<inf>2-: X</inf>Co<inf>x</inf>P nanocrystals for the hydrogen evolution reaction

Junfeng Liu, Zhenxing Wang, Jeremy David, Jordi Llorca, Junshan Li, Xiaoting Yu, Alexey Shavel, Jordi Arbiol, Michaela Meyns, Andreu Cabot

    Research output: Contribution to journalArticleResearchpeer-review

    25 Citations (Scopus)

    Abstract

    © The Royal Society of Chemistry 2018. A cost-effective and scalable approach was developed to produce monodisperse Ni2-xCoxP nanocrystals (NCs) with composition tuned over the entire range (0 ≤ x ≤ 2). Ni2-xCoxP NCs were synthesized using low-cost, stable and low-toxicity triphenyl phosphite (TPP) as a phosphorus source, metal chlorides as metal precursors and hexadecylamine (HDA) as a ligand. The synthesis involved the nucleation of amorphous Ni-P and its posterior crystallization and simultaneous incorporation of Co. The composition, size and morphology of the Ni2-xCoxP NCs could be controlled simply by varying the ratio of Ni and Co precursors and the amounts of TPP and HDA. Ternary Ni2-xCoxP-based electrocatalysts exhibited enhanced electrocatalytic activity toward the hydrogen evolution reaction (HER) compared to binary phosphides. In particular, NiCoP electrocatalysts displayed the lowest overpotential of 97 mV at J = 10 mA cm-2 and an excellent long-term stability. DFT calculations of the Gibbs free energy for hydrogen adsorption at the surface of Ni2-xCoxP NCs showed NiCoP to have the most appropriate composition to optimize this parameter within the whole Ni2-xCoxP series. However, the hydrogen adsorption energy was demonstrated not to be the only parameter controlling the HER activity in Ni2-xCoxP.
    Original languageEnglish
    Pages (from-to)11453-11462
    JournalJournal of Materials Chemistry A
    Volume6
    Issue number24
    DOIs
    Publication statusPublished - 1 Jan 2018

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