A unique oxygen ligand environment facilitates water oxidation in hole-doped IrNiOx core–shell electrocatalysts

Nong, Hong Nhan; Reier, Tobias; Oh, Hyung Suk; Gliech, Manuel; Paciok, Paul; Vu, Thu Ha Thi; Teschner, Detre; Heggen, Marc; Petkov, Valeri; Schlögl, Robert; Jones, Travis E.; Strasser, Peter

doi:10.1038/s41929-018-0153-y

Cited by 492 publications

(565 citation statements)

References 66 publications

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“…This plot highlights the wide variety of electrolytes and concentration used in the literature. Interestingly, some of the highest mass activities correspond to Ir oxides alloyed with transition metals such as Ni, Co, Cu or Fe evaluated in 0.1 M HClO 4 , while some of the lowest activities have been obtained in H 2 SO 4 electrolytes . These results are in accordance with our results on Ir black nanoparticles (dotted lines in Figure ).…”

Section: Figurementioning

confidence: 99%

Electrolyte Effects on the Electrocatalytic Performance of Iridium‐Based Nanoparticles for Oxygen Evolution in Rotating Disc Electrodes

Arminio‐Ravelo

Jensen

et al. 2019

ChemPhysChem

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Proton exchange membrane water electrolysers are very promising renewable energy conversion devices that produce hydrogen from sustainable feedstocks. These devices are mainly limited by the sluggish kinetics of the oxygen evolution reaction (OER). Ir‐based nanoparticles are both reasonably active and stable for the OER in acidic media. The electrolyte composition and the pH may play a crucial role in electrocatalysis, yet they have been widely overlooked for the OER. Herein, we present a study on the effects of the composition and concentration of the electrolyte on commercial Ir black nanoparticles using concentrations of 0.05 M, 0.1 M and 0.5 M of both sulphuric and perchloric acid. The results show an important effect of the electrolyte composition on the catalytic performance of the Ir nanoparticles. The concentration of H2SO4 interferes on the oxidation of Ir and decreases the catalytic performance of the catalyst. HClO4 does not show strong interferences in the electrochemistry of Ir. Higher catalytic performances are observed in HClO4 electrolytes in comparison to H2SO4 with little effect of the concentration of HClO4.

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Section: Figurementioning

confidence: 99%

Electrolyte Effects on the Electrocatalytic Performance of Iridium‐Based Nanoparticles for Oxygen Evolution in Rotating Disc Electrodes

Arminio‐Ravelo

Jensen

et al. 2019

ChemPhysChem

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“…Theo xygen reduction reaction (ORR) and oxygen evolution reaction (OER) play ac rucial role in renewable energy provision schemes,which are relevant for e.g.,metalair batteries,fuel cells and electrolyzers. [1] Many efforts have been made to develop efficient bifunctional ORR/OER catalysts,w hich are typically based on precious metal oxides, [2] perovskites [3] and non-noble metal oxides. [4] Among alarge number of state-of-the-art electrode materials capable to efficiently catalyze both reactions,m etal-organic frameworks (MOFs) and their derivatives have attracted considerable attention due to their tunable lattice structures, porosity and well-defined compositions,j ust to name af ew aspects.…”

Section: Introductionmentioning

confidence: 99%

Advanced Bifunctional Oxygen Reduction and Evolution Electrocatalyst Derived from Surface‐Mounted Metal–Organic Frameworks

et al. 2020

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Metal–organic frameworks (MOFs) and their derivatives are considered as promising catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which are important for many energy provision technologies, such as electrolyzers, fuel cells and some types of advanced batteries. In this work, a “strain modulation” approach has been applied through the use of surface‐mounted NiFe‐MOFs in order to design an advanced bifunctional ORR/OER electrocatalyst. The material exhibits an excellent OER activity in alkaline media, reaching an industrially relevant current density of 200 mA cm−2 at an overpotential of only ≈210 mV. It demonstrates operational long‐term stability even at a high current density of 500 mA cm−2 and exhibits the so far narrowest “overpotential window” ΔEORR‐OER of 0.69 V in 0.1 m KOH with a mass loading being two orders of magnitude lower than that of benchmark electrocatalysts.

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“…4H + + O 2 + 4e À ). [15][16][17] Recently,Ir-based perovskites have been reported as promising candidates in acidic media. [7][8][9][10][11] Thef ew materials established as suitable OER catalysts in acidic media are mostly Ir-based metal oxides,such as rutile IrO 2 , [12,13] electrodeposited IrO x [14] or more recently Ni-substituted IrO x .…”

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confidence: 99%

“…[7][8][9][10][11] Thef ew materials established as suitable OER catalysts in acidic media are mostly Ir-based metal oxides,such as rutile IrO 2 , [12,13] electrodeposited IrO x [14] or more recently Ni-substituted IrO x . [15][16][17] Recently,Ir-based perovskites have been reported as promising candidates in acidic media. [18][19][20] Thehigh OER activity of these Ir-based perovskites was ascribed to the formation of electrophilic O (IÀ) surface species favoring the nucleophilic attack of water.…”

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confidence: 99%

A Dissolution/Precipitation Equilibrium on the Surface of Iridium‐Based Perovskites Controls Their Activity as Oxygen Evolution Reaction Catalysts in Acidic Media

et al. 2019

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Recently,I r V -based perovskite-like materials were proposed as oxygen evolution reaction (OER) catalysts in acidic media with promising performance.H owever,i ridium dissolution and surface reconstruction were observed, questioning the real active sites on the surface of these catalysts.In this work, Sr 2 MIr (V) O 6 (M = Fe,Co) and Sr 2 Fe 0.5 Ir 0.5 (V) O 4 were explored as OER catalysts in acidic media. Their activities were observed to be roughly equal to those previously reported for La 2 LiIrO 6 or Ba 2 PrIrO 6 .C oupling electrochemical measurements with iridium dissolution studies under chemical or electrochemical conditions,w es howt hat the deposition of an IrO x layer on the surface of these perovskites is responsible for their OER activity.F urthermore,w ee xperimentally reconstruct the iridium Pourbaix diagram, whichw ill help guide future researchi nc ontrolling the dissolution/precipitation equilibrium of iridium species for the design of better Irbased OER catalysts.The electrochemical production of hydrogen fuel by water splitting has long been explored as ap otential way to store clean and renewable energy.T he key challenge for water splitting lies in improving the efficiency of the kinetically slow, rate-limiting oxygen evolution reaction (OER) (2 H 2 O! 4H + + O 2 + 4e À ). [1,2] While alarge variety of transition metal oxides have been studied as promising OER catalysts in alkaline media, [3][4][5][6] thedesign of active and stable catalysts in acidic media has proven challenging. [7][8][9][10][11] Thef ew materials established as suitable OER catalysts in acidic media are mostly Ir-based metal oxides,such as rutile IrO 2 , [12,13] 14] or more recently Ni-substituted IrO x . [15][16][17] Recently,Ir-based perovskites have been reported as promising candidates in acidic media. [18][19][20] Thehigh OER activity of these Ir-based perovskites was ascribed to the formation of electrophilic O (IÀ) surface species favoring the nucleophilic attack of water. [11,20,21] However,dissolution of iridium, alkali and/or rare earth elements in acidic electrolytes has been observed after close examinations of some Ir V -based perovskites,such as La 2 LiIr (V) O 6[20] and Ba 2 PrIr (V) O 6 , [7,19] indicating their drastic structural instabilities in harsh acidic conditions. [12] Furthermore,the presence of IrO 2 nanoparticles was revealed on the surface of La 2 LiIr (V) O 6 after cycling. [8] Given this array of observations,alegitimate question arises over the origin of the OER activity on the surface of these perovskites.Therefore,itisimportant to understand the OER mechanism of these Ir V -based perovskites,aswell as the effect of iridium dissolution on their catalytic behaviors,inorder to improve their performances and/or guide future research in designing new active and stable OER catalysts in acidic media.We herein investigate the catalytic behaviors of three Ir Vbased OER catalysts in acidic media, Sr 2 MIr (V) O 6 (M = Fe, Co) with ad ouble perovskite structure and Sr 2 Fe 0.5 Ir 0.5 (V) O 4 with a...

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A unique oxygen ligand environment facilitates water oxidation in hole-doped IrNiOx core–shell electrocatalysts

Cited by 492 publications

References 66 publications

Electrolyte Effects on the Electrocatalytic Performance of Iridium‐Based Nanoparticles for Oxygen Evolution in Rotating Disc Electrodes

Electrolyte Effects on the Electrocatalytic Performance of Iridium‐Based Nanoparticles for Oxygen Evolution in Rotating Disc Electrodes

Advanced Bifunctional Oxygen Reduction and Evolution Electrocatalyst Derived from Surface‐Mounted Metal–Organic Frameworks

A Dissolution/Precipitation Equilibrium on the Surface of Iridium‐Based Perovskites Controls Their Activity as Oxygen Evolution Reaction Catalysts in Acidic Media

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