AlFe2B2 pre-catalyst produces a nanocrystalline Fe3O4 shell in alkaline media. The system acts as a remarkably stable water oxidation electrocatalyst.

With a Curie temperature just above room temperature, AlFe 2 B 2 is a useful magnetocaloric material composed of earth-abundant elements. We employ temperature-dependent high resolution synchrotron X-ray diffraction to establish with high certainly that the paramagnetic to ferromagnetic transition in AlFe 2 B 2 is second order, showing no discontinuity in lattice parameters or cell volume. Nevertheless, the lattice parameters undergo anisotropic changes across the transition with distinct differences in the thermal expansion coefficients. While the a and b lattice parameters show positive thermal expansion, c shows negative thermal expansion. We link these changes to the respective interatomic distances to determine the contribution of magnetism to the anisotropic structural evolution. The work underpins the possible role of magnetostructural coupling in driving the magnetocaloric effect in AlFe 2 B 2 .

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.