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5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Synergistic Co-Ir/Ru Composite Electrocatalysts Impart Efficient and Durable Oxygen Evolution Catalysis in Acid

Exploring highly active and robust catalysts, which have low precious metal content, to boost the kinetically sluggish oxygen evolution reaction (OER) is a key concern for hydrogen production via proton exchange membrane water electrolysis (PEMWE). Here, in this work, rational engineering of the morphology and the local geometric ligand environment of Ir and Ru catalysts are presented by using defect-rich, lanthanum- and lithium-doped Co 3 O 4 nanofiber (LLCF) as substrate that promotes the electrocatalytic OER. Two catalysts, IrCoOx@LLCF and RuCoOx@LLCF, achieve mass activities of 1013.5 A g Ir –1 and 1911.4 A g Ru –1 in 0.1 M HClO 4 at 300 mV overpotential, respectively, which are 26 and 50 times higher than that of commercial IrO 2 and RuO 2 . Operando X-ray absorption spectroscopy unveils the reversible structure of IrCoOx during the OER and the suppression of over-oxidation of Co and Ir, giving rise to high stability. Density functional theory calculations reveal that the local geometric ligand engineering optimizes the binding of oxygenated species to the active sites, resulting in strongly enhanced catalytic activity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on Co3Ir by Materials Project

IrCo3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ir is bonded to twelve equivalent Co atoms to form IrCo12 cuboctahedra that share corners with twelve equivalent IrCo12 cuboctahedra, edges with twenty-four equivalent CoCo8Ir4 cuboctahedra, faces with six equivalent IrCo12 cuboctahedra, and faces with twelve equivalent CoCo8Ir4 cuboctahedra. All Ir–Co bond lengths are 2.53 Å. Co is bonded to four equivalent Ir and eight equivalent Co atoms to form CoCo8Ir4 cuboctahedra that share corners with twelve equivalent CoCo8Ir4 cuboctahedra, edges with eight equivalent IrCo12 cuboctahedra, edges with sixteen equivalent CoCo8Ir4 cuboctahedra, faces with four equivalent IrCo12 cuboctahedra, and faces with fourteen equivalent CoCo8Ir4 cuboctahedra. All Co–Co bond lengths are 2.53 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CoIr by Materials Project

IrCo crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Ir is bonded to six equivalent Ir and six equivalent Co atoms to form distorted IrCo6Ir6 cuboctahedra that share corners with eighteen equivalent IrCo6Ir6 cuboctahedra, edges with six equivalent IrCo6Ir6 cuboctahedra, edges with twelve equivalent CoCo6Ir6 cuboctahedra, faces with eight equivalent IrCo6Ir6 cuboctahedra, and faces with twelve equivalent CoCo6Ir6 cuboctahedra. All Ir–Ir bond lengths are 2.67 Å. All Ir–Co bond lengths are 2.57 Å. Co is bonded to six equivalent Ir and six equivalent Co atoms to form distorted CoCo6Ir6 cuboctahedra that share corners with eighteen equivalent CoCo6Ir6 cuboctahedra, edges with six equivalent CoCo6Ir6 cuboctahedra, edges with twelve equivalent IrCo6Ir6 cuboctahedra, faces with eight equivalent CoCo6Ir6 cuboctahedra, and faces with twelve equivalent IrCo6Ir6 cuboctahedra. All Co–Co bond lengths are 2.67 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CoIr by Materials Project

IrCo crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Ir sites. In the first Ir site, Ir is bonded to six equivalent Ir and six Co atoms to form distorted IrCo6Ir6 cuboctahedra that share corners with twelve IrCo6Ir6 cuboctahedra, edges with twelve IrCo6Ir6 cuboctahedra, edges with twelve CoCo6Ir6 cuboctahedra, faces with six equivalent IrCo6Ir6 cuboctahedra, and faces with twelve CoCo6Ir6 cuboctahedra. All Ir–Ir bond lengths are 2.65 Å. All Ir–Co bond lengths are 2.58 Å. In the second Ir site, Ir is bonded to ten equivalent Ir and six Co atoms to form distorted IrCo6Ir10 cuboctahedra that share corners with ten CoCo6Ir6 cuboctahedra, corners with twelve IrCo6Ir6 cuboctahedra, edges with eight CoCo6Ir6 cuboctahedra, edges with sixteen IrCo6Ir6 cuboctahedra, faces with sixteen equivalent IrCo6Ir10 cuboctahedra, and faces with eighteen CoCo6Ir6 cuboctahedra. There are a spread of Ir–Ir bond distances ranging from 2.65–5.30 Å. All Ir–Co bond lengths are 2.58 Å. There are three inequivalent Co sites. In the first Co site, Co is bonded to six equivalent Ir and six equivalent Co atoms to form distorted CoCo6Ir6 cuboctahedra that share corners with twelve CoCo6Ir6 cuboctahedra, edges with twelve equivalent IrCo6Ir6 cuboctahedra, edges with twelve CoCo6Ir6 cuboctahedra, faces with six equivalent CoCo6Ir6 cuboctahedra, and faces with twelve equivalent IrCo6Ir6 cuboctahedra. All Co–Co bond lengths are 2.65 Å. In the second Co site, Co is bonded to six Ir and six equivalent Co atoms to form distorted CoCo6Ir6 cuboctahedra that share corners with five equivalent IrCo6Ir10 cuboctahedra, corners with twelve CoCo6Ir6 cuboctahedra, edges with ten IrCo6Ir6 cuboctahedra, edges with twelve CoCo6Ir6 cuboctahedra, faces with six equivalent CoCo6Ir6 cuboctahedra, and faces with fifteen IrCo6Ir6 cuboctahedra. All Co–Ir bond lengths are 2.58 Å. All Co–Co bond lengths are 2.65 Å. In the third Co site, Co is bonded to six Ir and six equivalent Co atoms to form distorted CoCo6Ir6 cuboctahedra that share corners with five equivalent IrCo6Ir10 cuboctahedra, corners with twelve CoCo6Ir6 cuboctahedra, edges with ten IrCo6Ir6 cuboctahedra, edges with twelve CoCo6Ir6 cuboctahedra, faces with six equivalent CoCo6Ir6 cuboctahedra, and faces with fifteen IrCo6Ir6 cuboctahedra. All Co–Co bond lengths are 2.65 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Co3Ir by Materials Project

IrCo3 is beta-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Ir is bonded to six equivalent Ir and six equivalent Co atoms to form IrCo6Ir6 cuboctahedra that share corners with six equivalent IrCo6Ir6 cuboctahedra, corners with twelve equivalent CoCo12 cuboctahedra, edges with six equivalent IrCo6Ir6 cuboctahedra, edges with twelve equivalent CoCo9Ir3 cuboctahedra, faces with six equivalent IrCo6Ir6 cuboctahedra, and faces with fourteen CoCo12 cuboctahedra. All Ir–Ir bond lengths are 2.62 Å. All Ir–Co bond lengths are 2.61 Å. There are two inequivalent Co sites. In the first Co site, Co is bonded to twelve Co atoms to form CoCo12 cuboctahedra that share corners with six equivalent CoCo12 cuboctahedra, corners with twelve equivalent IrCo6Ir6 cuboctahedra, edges with eighteen CoCo12 cuboctahedra, faces with two equivalent IrCo6Ir6 cuboctahedra, and faces with eighteen CoCo12 cuboctahedra. There are six shorter (2.47 Å) and six longer (2.62 Å) Co–Co bond lengths. In the second Co site, Co is bonded to three equivalent Ir and nine Co atoms to form distorted CoCo9Ir3 cuboctahedra that share corners with eighteen equivalent CoCo9Ir3 cuboctahedra, edges with six equivalent IrCo6Ir6 cuboctahedra, edges with twelve CoCo12 cuboctahedra, faces with six equivalent IrCo6Ir6 cuboctahedra, and faces with fourteen CoCo12 cuboctahedra. All Co–Co bond lengths are 2.62 Å.

36 MATERIALS SCIENCE↗