Abstract
We report a highly active and durable water oxidation electrocatalyst based on cubic nanocages with a composition of Ir44Pd10, together with well-defined {100} facets and porous walls of roughly 1.1 nm in thickness. Such nanocages substantially outperform all the water oxidation electrocatalysts reported in literature, with an overpotential of only 226 mV for reaching 10 mA cm−2geo at a loading of Ir as low as 12.5 μgIr cm−2 on the electrode in acidic media. When benchmarked against a commercial Ir/C electrocatalyst at 250 mV of overpotential, such a nanocage-based catalyst not only shows enhancements (18.1- and 26.2-fold, respectively) in terms of mass (1.99 A mg−1Ir) and specific (3.93 mA cm−2Ir) activities, but also greatly enhanced durability. The enhancements can be attributed to a combination of multiple merits, including a high utilization efficiency of Ir atoms and an open structure beneficial to the electrochemical oxidation of Ir to the active form of IrOx.
Original language | English |
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Pages (from-to) | 7244-7248 |
Number of pages | 5 |
Journal | Angewandte Chemie - International Edition |
Volume | 58 |
Issue number | 22 |
DOIs | |
State | Published - May 27 2019 |
Funding
This work was supported in part by a grant from the Department of Energy-Basic Energy Sciences, Division of Chemical Sciences (DE-FG02-05ER15731) and start-up funds from the Georgia Institute of Technology. As a visiting Ph.D. student, J.Z. was also partially supported by fellowships from the China Scholarship Council (CSC) and the College of Chemical Engineering of Nanjing Tech University. Part of the electron microscopy work was performed through a user project supported by the ORNL≫s Center for Nanophase Materials Sciences, which is a U.S. Department of Energy Office of Science User Facility. This work was supported in part by a grant from the Department of Energy-Basic Energy Sciences, Division of Chemical Sciences (DE-FG02-05ER15731) and start-up funds from the Georgia Institute of Technology. As a visiting Ph.D. student, J.Z. was also partially supported by fellowships from the China Scholarship Council (CSC) and the College of Chemical Engineering of Nanjing Tech University. Part of the electron microscopy work was performed through a user project supported by the ORNL's Center for Nanophase Materials Sciences, which is a U.S. Department of Energy Office of Science User Facility.
Keywords
- acidic media
- iridium
- nanocages
- ultrathin walls
- water oxidation