Understanding the spatial configurations of Sm₂O₃ in ZnO surface-loaded or embedded for the electrocatalytic oxygen evolution reaction

Recently, the oxygen evolution reaction (OER) has been accelerated with addition of samarium (Sm) to the fabricated electrocatalyst. Notably, the spatial dispersal of Sm in their hosts can impact the ability to use Sm species as additives and improve electrocatalytic performance. This study investigates two distinct catalytic designs in-depth to comprehend the diverse spatial arrangements that influence the features of OER. Sm₂O₃-loaded ZnO on the surface (Sm-Zn-L) and Sm₂O₃-embedded ZnO (Sm-Zn-E) are the two possible formations. Sm-Zn-E catalysts possessed a lower overpotential (419 mV for 10 mA cm⁻²), Tafel slope (89 mV dec⁻¹) along with good stability up till 40 h and 1000 cycles as compared to Sm-Zn-L (448 mV and 159 mV dec⁻¹). This explains entrenched arrangements benefit for OER. Introducing minute clusters of Sm₂O₃ into the ZnO improves the precise surface area, number of surface flaws, and the efficiency with which the electronic assemblies of the surface-active sites are optimized. Due to this, Sm-Zn-E has a higher OER than Sm-Zn-L. The above information offers a realistic framework for reordering catalysts to increase their spatial performance. Graphical abstract: [Figure not available: see fulltext.].