Nanoparticle-Decorated Ultrathin La(2)O(3) Nanosheets as an Efficient Electrocatalysis for Oxygen Evolution Reactions

Electrochemical catalysts for oxygen evolution reaction are a critical component for many renewable energy applications. To improve their catalytic kinetics and mass activity are essential for sustainable industrial applications. Here, we report a rare-earth metal-based oxide electrocatalyst comprised of ultrathin amorphous La(2)O(3) nanosheets hybridized with uniform La(2)O(3) nanoparticles (La(2)O(3)@NP-NS). Significantly improved OER performance is observed from the nanosheets with a nanometer-scale thickness. The as-synthesized 2.27-nm La(2)O(3)@NP-NS exhibits excellent catalytic kinetics with an overpotential of 310 mV at 10 mA cm(−2), a small Tafel slope of 43.1 mV dec(−1), and electrochemical impedance of 38 Ω. More importantly, due to the ultrasmall thickness, its mass activity, and turnover frequency reach as high as 6666.7 A g(−1) and 5.79 s(−1), respectively, at an overpotential of 310 mV. Such a high mass activity is more than three orders of magnitude higher than benchmark OER electrocatalysts, such as IrO(2) and RuO(2). This work presents a sustainable approach toward the development of highly efficient electrocatalysts with largely reduced mass loading of precious elements. [Image: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s40820-020-0387-5) contains supplementary material, which is available to authorized users.