The nature of phase separation in Ir–Sn–O ternary oxide electrocatalyst

Wang, Xin; Deng, Fenyong; Tang, Zhenwei; Wu, Bo; Tang, Dian; Lin, Wei

doi:10.1016/j.jeurceramsoc.2013.07.002

Cited by 8 publications

(17 citation statements)

References 35 publications

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“…Nb2O5, TiO2, Ta2O3, Ta2O5) when combined with IrO2. For Sn-based materials, the similar lattice parameters, the same valency of Ir(IV) and Sn(IV), similar radii, comparable electronegativities, and interfacial energies between IrO2-rutile and SnO2 favour the formation of mixed oxides [49][50][51][52]. In the following paragraphs, we will discuss the accompanying consequences of this dependency for (1) the activities and (2) the durability of the prepared catalysts.…”

Section: Liquid Atomic Layer Depositionmentioning

confidence: 93%

Towards maximized utilization of iridium for the acidic oxygen evolution reaction

et al. 2019

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The reduction in noble metal content for efficient oxygen evolution catalysis is a crucial aspect towards the large scale commercialisation of polymer electrolyte membrane electrolyzers. Since catalytic stability and activity are inversely related, long service lifetime still demands large amounts of low-abundant and expensive iridium. In this manuscript we elaborate on the concept of maximizing the utilisation of iridium for the oxygen evolution reaction. By combining different tin oxide based support materials with liquid atomic layer deposition of iridium oxide, new possibilities are opened up to grow thin layers of iridium oxide with tuneable noble metal amounts. In-situ, time-and potential-resolved dissolution experiments reveal how the stability of the substrate and the catalyst layer thickness directly affect the activity and stability of deposited iridium oxide. Based on our results, we elaborate on strategies how to obtain stable and active catalysts with maximized iridium utilisation for the oxygen evolution reaction and demonstrate how the activity and durability can be tailored correspondingly. Our results highlight the potential of utilizing thin noble metal films with earth abundant support materials for future catalytic applications in the energy sector.

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Section: Liquid Atomic Layer Depositionmentioning

confidence: 93%

Towards maximized utilization of iridium for the acidic oxygen evolution reaction

et al. 2019

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“…[13b] Another more Figure 8. Ir-Sn-oxide equilibriumphase diagram,I SS:iridium-rich solid solution;S SS:tin-rich solid solution; [58] reprinted with permission from Elsevier.…”

Section: Morphologymentioning

confidence: 99%

“…[39,66, 95a] In mixed catalysts,temperature is also ac rucial factor in obtaining as ingle-phase structure or ametastable phase as asynthesis intermediate. [58,98] It has been shown that precise temperature control (within af ew 8 8C) and reduced synthesis temperature (from 450 to 250 8 8Cfor IrO 2 )can produce more active catalysts that can be more stable than their counterparts calcined at medium temperatures (350 8 8C).…”

Section: Synthesis Temperaturementioning

confidence: 99%

The Stability Challenges of Oxygen Evolving Catalysts: Towards a Common Fundamental Understanding and Mitigation of Catalyst Degradation

et al. 2017

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This Review addresses the technical challenges, scientific basis, recent progress, and outlook with respect to the stability and degradation of catalysts for the oxygen evolution reaction (OER) operating at electrolyzer anodes in acidic environments with an emphasis on ion exchange membrane applications. First, the term "catalyst stability" is clarified, as well as current performance targets, major catalyst degradation mechanisms, and their mitigation strategies. Suitable in situ experimental methods are then evaluated to give insight into catalyst degradation and possible pathways to tune OER catalyst stability. Finally, the importance of identifying universal figures of merit for stability is highlighted, leading to a comprehensive accelerated lifetime test that could yield comparable performance data across different laboratories and catalyst types. The aim of this Review is to help disseminate and stress the important relationships between structure, composition, and stability of OER catalysts under different operating conditions.

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“…Although this calculation method has been validated for some complex oxide/nitride systems, one general challenge remains in the determination of τ at Step 4. Typically, an estimation is made for the interaction parameter near a critical temperature ( T c ), and then the Ω( x , T c )− T c are substituted into Eq.…”

Section: Introductionmentioning

confidence: 99%

Phase Stability and Phase Structure of Ru–Ti–O Complex Oxide Electrocatalyst

et al. 2015

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Phase stability of (Ru 1x ,Ti x )O 2 solid solution was investigated via materials computation and X-ray diffraction phase analyses. The unit cell volume of (Ru 1x ,Ti x )O 2 was found not increasing monotonously with the fraction of TiO 2 , making the volume-composition relationship no longer suitable for the quantitative phase analysis. A monotonous nonlinear c/a-x relation obtained from the ab initio density functional theory (DFT) computation was proved critical to achieving accurate phase analysis results. Gibbs free energy of mixing and its derivatives were determined for (Ru 1x ,Ti x )O 2 by a combination of DFT and thermodynamic calculations, where approximation of the temperature dependence of the interaction parameter (Ω) played a critical role. It was found that the conventional approximation method of arbitrarily choosing a value [ [10,25] kJ (mole of atoms) -1 for Ω near a critical temperature of a solid solution structure failed to predict the correct symmetry and span of the miscibility gap for (Ru 1x ,Ti x )O 2 . In comparison, Ω calculated from disordered (Ru 1x ,Ti x )O 2 was found a good approximation at the critical temperature. The calculated miscibility gap for (Ru 1x ,Ti x )O 2 , therefore, showed good agreement with the accurate quantitative phase analysis results for the samples prepared by a sol-gel method.

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The nature of phase separation in Ir–Sn–O ternary oxide electrocatalyst

Cited by 8 publications

References 35 publications

Towards maximized utilization of iridium for the acidic oxygen evolution reaction

Towards maximized utilization of iridium for the acidic oxygen evolution reaction

The Stability Challenges of Oxygen Evolving Catalysts: Towards a Common Fundamental Understanding and Mitigation of Catalyst Degradation

Phase Stability and Phase Structure of Ru–Ti–O Complex Oxide Electrocatalyst

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