Polar Layered Intermetallic LaCo₂P₂ as a Water Oxidation Electrocatalyst

Abstract

We investigate LaCo 2 P 2 as an electrocatalytic material for oxygen evolution reaction (OER) under alkaline and acidic conditions. This layered intermetallic material was prepared via Sn-flux high-temperature annealing. The electrocatalytic ink, prepared with the ball-milled LaCo 2 P 2 catalyst at the mass loading of 0.25 mg/cm 2 , shows OER activity at pH = 14, reaching current densities of 10, 50, and 100 mA/cm 2 under the overpotential of 400, 440, and 460 mV, respectively. Remarkably, the electrocatalytic performance remains constant for at least 4 days. Transmission electron microscopy reveals the formation of a catalytically active CoO x shell around the pre-catalyst LaCo 2 P 2 core during the alkaline OER. The core serves as a robust support for the in situ -formed electrocatalytic system. Similar studies under pH = 0 reveal the rapid deterioration of LaCo 2 P 2 , with the formation of LaPO 4 and amorphous cobalt oxide. This study shows the viability of layered intermetallics as stable OER electrocatalysts, although further developments are required to improve the electrocatalytic performance and increase the stability at lower pH values.

Oxygen Vacancy-Originated Inorganic Proton Relay for the Oxygen Evolution Reaction: Fast Proton Hopping via La-Doped Praseodymium Carbonate Hydroxide

“…The cyclic voltammograms obtained in 0.1 M KOH and the relevant plot of current densities against sweeping rates ranging from 5 to 140 mV s –1 at (c) NF/La-PrCH and (d) NF/Sr–La–PrCH. The comparison of the required overpotentials of the (e) as-prepared electrodes together and the (f) recently published OER electrocatalysts to reach J = 10 mA cm –2 (references are − , respectively, from left to right), with that of our work.…”

Metal–Organic Skeleton-Derived P-CoFe2O4@CN Nanoparticles Embedded with Nitrogen-Doped Carbon as Effective Electrocatalysts for the Oxygen Evolution Reaction

“…25 Figure 3a shows that the ratio and peak width of D and G bands indicate the degree of disorder defects in the material, and the ratio of phosphide bimetallic oxides are slightly higher than those of other phosphide monometallic oxides, with a value of 1.05; thus, P-CoFe 2 O 4 @CN shows better electrochemical performance. 26,27 The crystal structure of P-CoFe 2 O 4 @CN was resolved by X-ray diffraction (XRD). According to the corresponding plots shown in Figure 3b, the presence of CoFe 2 O 4 diffraction peaks can be seen.…”

Polar Metals Taxonomy for Materials Classification and Discovery

“…Finally, the properties and applications of polar metals are not yet fully appreciated. Recent work on topological phonons indicates that polar metals are ideal candidates to host this recently described phenomenon [120], while the potential for polar metals to impact the fields of photovoltaics [121], energy harvesting [122,123], catalysis [124], microelectronic [125][126][127], optoelectronic, photonic and plasmonic devices [100,101,[128][129][130][131][132][133][134], and quantum information systems [135] remains largely untapped.…”