Al-Induced In Situ Formation of Highly Active Nanostructured Water-Oxidation Electrocatalyst Based on Ni-Phosphide

Abstract

We report a simple low-cost concept for the preparation of water-oxidation electrocatalyst via modification of self-supported Ni 5 P 4 −Ni 2 P foam catalyst precursor with Al. As an anode for alkaline oxygen evolution reaction, this material exhibits an impressive Tafel slope of 27 mV dec −1 and offers anodic current densities of 10, 100, and 300 mA cm −2 at overpotentials of merely 180, 247, and 312 mV, respectively. Moreover, the anode demonstrates high operational stability, as reflected by a steady-state performance for more than 8 days. Combining state-of-the-art electron microscopy and photoelectron spectroscopy, we investigated the role of the Al dopant in the formation of active Ni(OH) 2 /NiO/Ni 5 P 4 −Ni 2 P nanocatalyst, which exhibits oxygen-evolving activity among the highest reported to date.

Crystallographic facet selective HER catalysis: exemplified in FeP and NiP2 single crystals

“…45 The more difficult to remove ca. 5 nm layer on top of the m-NiP 2 single-crystal material is compositionally similar to the oxidation layers on as-prepared polycrystalline 17 and nanostructured Ni phosphide catalysts, 45,46 consistent with the previous interpretation of the Ni 2p 3/2 component at BE of 857.5 AE 0.2 eV as primarily Ni phosphate. Finally, the difficulty in removing the phosphate overlayer from m-NiP 2 , highlights the apparently signicant effect of the specic transition metal and bulk stoichiometry on the properties of the oxidized overlayers.…”

Kinetically Stable Oxide Overlayers on Mo3P Nanoparticles Enabling Lithium–Air Batteries with Low Overpotentials and Long Cycle Life

“…Electrocatalytic properties of transition metal phosphides have received great attention and been subject of theoretical and experimental studies. [ 12–16 ] Wang et al. demonstrated a convenient and straightforward approach to the synthesis of a 3D self‐supported Ni 5 P 4 ‐Ni 2 P nanosheet cathode, very stable in acidic medium with an outstanding hydrogen evolution reaction (HER) activity.…”

Hollow Porous Heterometallic Phosphide Nanocubes for Enhanced Electrochemical Water Splitting

“…Metallic phosphides have emerged as burgeoning nonprecious metal electrocatalysts for both HER and OER owing to their low cost and high electrical conductivity . Of note, metal phosphides would be partially oxidized to corresponding metal oxide or (oxy)hydroxides during OER catalysis and form unique heterostructures.…”

“…Of note, metal phosphides would be partially oxidized to corresponding metal oxide or (oxy)hydroxides during OER catalysis and form unique heterostructures. Due to the improved conductivity compared with the corresponding metal oxides/hydroxides and the synergistic electronic interactions between the different components, the composite electrocatalysts usually exhibit remarkably enhanced OER catalytic activities compared with the simple corresponding metal oxides/hydroxides synthesized directly . Nevertheless, high overpotentials are still needed to drive HER and OER unless the structure and composition of the metal phosphide catalysts are rationally designed.…”