Vertically Stacked Amorphous Ir/Ru/Ir Oxide Nanosheets for Boosted Acidic Water Splitting
Junmin Li, Geng Wu, Zixiang Huang, Xiao Han, Bei Wu, Peigen Liu, Haohui Hu, Ge Yu, Xun Hong
Abstract
High Resolution Image Download MS PowerPoint Slide Integrating multiple functional components into vertically stacked heterostructures offers a prospective approach to manipulating the physicochemical properties of materials. The synthesis of vertically stacked heterogeneous noble metal oxides remains a challenge. Herein, we report a surface segregation approach to create vertically stacked amorphous Ir/Ru/Ir oxide nanosheets (NSs). Cross-sectional high-angle annular darkfield scanning transmission electron microscopy images demonstrate a three-layer heterostructure in the amorphous Ir/Ru/Ir oxide NSs, with IrO x layers located on the upper and lower surfaces, and a layer of RuO x sandwiched between the two IrO x layers. The vertically stacked heterostructure is a result of the diffusion of Ir atoms from the amorphous IrRuO x solid solution to the surface. The obtained A-Ir/Ru/Ir oxide NSs display an ultralow overpotential of 191 mV at 10 mA cm –2 toward acid oxygen evolution reaction and demonstrate excellent performance in a proton exchange membrane water electrolyzer, which requires only 1.63 V to achieve 1 A cm –2 at 60 °C, with virtually no activity decay observed after a 1300 h test.