Understanding the spatial configurations of Sm2O3 in NiO interfaces Embedded-Loaded for Electrocatalytic OER process

The efficacy of the oxygen evolution reaction (OER) can be enhanced by adding samarium (Sm) species to electrocatalysts as was recently found. Significantly, the spatial dispersal of Sm substances in the NiO would define their individual aids to promote electrocatalytic activity, which in turn affects the accessibility of Sm substance as a dopant material. In this work, we perform in-depth studies of two different configurations of electrocatalyst, Sm2O3-embedded NiO (Sm-NiO-E) and Sm2O3-surface-loaded NiO (Sm-NiO-L), to investigate the consequence of their distinctive configuration on OER activity. The Sm-NiO-E electrocatalysts exhibit an overpotential (ɳ) of 409 mV @ 10 mA cm-2 and a Tafel slope of 81 mV dec‑1, representing the advantage of the embedded design for water splitting in contrast to Sm-NiO-L (484 mV and 147 mV dec‑1). Embedding configuration exhibited the small-sized Sm2O3 clusters into the host for a bigger special interfacial region and enriching interfacial defects allows Sm-NiO-E to have a greater O2 adsorption capability and better tuned electronic assemblies of the interfacial active region. These results provide a valuable guide for designing electrocatalysts with different spatial layouts to enhance their electrocatalytic properties.