Operando identification of site-dependent water oxidation activity on ruthenium dioxide single-crystal surfaces

Rao, Reshma R.; Kolb, Manuel J.; Giordano, Livia; Pedersen, Anne Juul; Katayama, Yu; Hwang, Jonathan; Mehta, Apurva; You, Hoydoo; Lunger, Jaclyn R.; Zhou, Hua; Halck, Niels Bendtsen; Vegge, Tejs; Chorkendorff, Ib; Stephens, Ifan E. L.; Shao‐Horn, Yang

doi:10.1038/s41929-020-0457-6

Cited by 242 publications

(253 citation statements)

References 70 publications

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“…[42][43][44][45] Only a very recent contribution of Rao et al analyzed the differences in catalytic activity of the (110), (100) and (101) surfaces of RuO2. 46 Despite the limitations in solvent representation among others, 40,41 the computed overpotentials are in good agreement with experiments and they support that the WNA mechanism is usually the applied mechanism. Indeed, in the crystalline (110) surface the water nucleophilic attack to the oxo-species is computed to be kinetically easier than the oxo-coupling of the I2M, 39,41,56 which suggests that at least for this surface the WNA mechanism is preferred.…”

Section: Introductionmentioning

confidence: 54%

Importance of the oxyl character on the IrO2 surface dependent catalytic activity for the oxygen evolution reaction

González

Heras-Domingo

Sodupe

et al. 2021

Journal of Catalysis

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The oxygen evolution reaction (OER) is considered to be the limiting step for the water splitting process. OER catalyst optimization is hindered because in the desirable acidic conditions the sole active catalysts are the expensive RuO2 and IrO2-based materials. Thus, the understanding of the factors controlling the reactivity of IrO2 is mandatory. In this contribution, we carried out spin polarized DFT (PBE-D2) periodic calculations to analyze the catalytic activities of the main ((110), (011), (100) and (001)) IrO2 surfaces. We considered the oxo-coupling (I2M) and water nucleophilic attack (WNA) mechanisms and computed the energy barriers of the chemical processes. Results show that the oxo-coupling and the water attack should be viewed as homolytic couplings and thus, the two processes only occur if the Ir=O species on the surfaces exhibit oxyl character. In these cases, the WNA mechanism is always easy and it becomes the most favorable pathway on the (110), (100) and (001) surfaces. In contrast, for the (011) facet the oxo-coupling is preferred. The required overpotentials for the four IrO2 surfaces depends on the feasibility to oxidize the Ir-OH to Ir-O species. However, if the oxidation is too favorable the resulting Ir=O species has no oxyl character and thus it does not further react. Therefore, the optimal catalyst shows a trade-off between the Ir-OH oxidation feasibility and the oxyl character of the surface Ir=O species. These two factors are tuned by the coordination of the unsaturated iridium sites: the (100) and (001) surfaces are more active than the (110) and (011). The key role of oxyl species has been shown to be important for molecular catalysts. However, the implications of oxyl species on IrO2 have rarely been mentioned. Present results show that the homogeneous and heterogeneous processes seem to have important similarities, thus suggesting that strategies used in one of the two fields could be transferred to the other.

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Section: Introductionmentioning

confidence: 54%

Importance of the oxyl character on the IrO2 surface dependent catalytic activity for the oxygen evolution reaction

González

Heras-Domingo

Sodupe

et al. 2021

Journal of Catalysis

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“…Based on HRTEM images (Figure S28, Supporting Information) of the derived Ru oxides and DFT calculations (Figures S42–S45, Supporting Information) of the OER mechanisms over different RuO2 surfaces, it can be concluded that the OER performance are the combined results of crystal surface, active surface area, and compositions. [ 40,53 ]…”

Section: Resultsmentioning

confidence: 99%

Ar/H₂/O₂‐Controlled Growth Thermodynamics and Kinetics to Create Zero‐, One‐, and Two‐Dimensional Ruthenium Nanocrystals towards Acidic Overall Water Splitting

Chen

2021

Adv Funct Materials

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A gas controlled formation strategy is developed to synthesize free‐standing 0D Ru nanoparticles, 1D Ru nanowires, and 2D Ru nanosheets through in‐situ regulated growth thermodynamics and kinetics with typical inert, reductive, and oxidative gases (Ar/H2/O2). The growth process of these Ru nanoparticles, nanowires, and nanosheets follow non‐directional growth, shape‐directed nanoparticle attachment, and directional growth mechanisms, respectively. Kinetics studies approve that H2 accelerates the reduction rate of the Ru precursor, while O2 depresses the reduction. The calculation results of the Gibbs surface free energy under different gas coverage further show that small molecules’ gas can effectively regulate the surface state and growth rate. These Ru nanocrystals exhibit excellent acidic water splitting performance. This work has systematically studied the influence of the small molecule gas on the formation process of the Ru nanocrystals, and provides an effective idea for the development and research of high‐performance nanomaterials in the future.

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“…[23] More recently, Shao-Horn's group studied the critical role of metal-oxygen bonds in triggering lattice-oxygen oxidation [24] and the local environment of active site. [25] Further studies showed a strong correlation between OER activity and oxygen p-band center relative to the Fermi level through theoretical calculations. [26] Other parameters, including cations in octahedral sites and transition metal 3d -O 2p hybridization, have been widely studied by metal doping or partial element substitution.…”

Section: Introductionmentioning

confidence: 97%

“…first demonstrated the relationship between transition metal e g occupancy and OER activity [23] . More recently, Shao‐Horn's group studied the critical role of metal‐oxygen bonds in triggering lattice‐oxygen oxidation [24] and the local environment of active site [25] . Further studies showed a strong correlation between OER activity and oxygen p‐band center relative to the Fermi level through theoretical calculations [26] .…”

Section: Introductionmentioning

confidence: 99%

The Effect of Cation Mixing in LiNiO₂ toward the Oxygen Evolution Reaction

et al. 2020

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Nickel‐based oxide catalysts are widely used for the oxygen evolution reaction (OER) in alkaline water electrolysis because of their low cost and high activity. In particular, the LiNiO2 catalyst shows high activity. Therefore, to elucidate the fundamental relationship between the local structure, catalyst activity, and stability of LiNiO2, we investigated the cation mixing effect by mixing sites of lithium and nickel ions in the LiNiO2‐based catalysts. Lower degrees of cation mixing lead to higher intrinsic OER activity but lower long‐term stability. The X‐ray absorption spectra (XAS) displayed a strong hybridization state of the Ni 3d and O 2p orbitals, which is the origin of the different catalytic activity behaviors. Meanwhile, operando XAS studies combined with potentiostatic stability tests and inductively coupled plasma optical emission spectrometry (ICP‐OES) demonstrated the Li ion loss during the OER process. Thus, the instability of LiNiO2 originates from de‐intercalation of Li ions and this irreversible structure change deteriorates the performance. Hindering the lithium diffusion path by cation mixing is a useful strategy for maintaining performance. This strategy could provide a novel design principle for compatible high activity and long‐lasting catalysts by reasonable structure mediation.

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Operando identification of site-dependent water oxidation activity on ruthenium dioxide single-crystal surfaces

Cited by 242 publications

References 70 publications

Importance of the oxyl character on the IrO2 surface dependent catalytic activity for the oxygen evolution reaction

Importance of the oxyl character on the IrO2 surface dependent catalytic activity for the oxygen evolution reaction

Ar/H₂/O₂‐Controlled Growth Thermodynamics and Kinetics to Create Zero‐, One‐, and Two‐Dimensional Ruthenium Nanocrystals towards Acidic Overall Water Splitting

The Effect of Cation Mixing in LiNiO₂ toward the Oxygen Evolution Reaction

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Operando identification of site-dependent water oxidation activity on ruthenium dioxide single-crystal surfaces

Cited by 242 publications

References 70 publications

Importance of the oxyl character on the IrO2 surface dependent catalytic activity for the oxygen evolution reaction

Importance of the oxyl character on the IrO2 surface dependent catalytic activity for the oxygen evolution reaction

Ar/H2/O2‐Controlled Growth Thermodynamics and Kinetics to Create Zero‐, One‐, and Two‐Dimensional Ruthenium Nanocrystals towards Acidic Overall Water Splitting

The Effect of Cation Mixing in LiNiO2 toward the Oxygen Evolution Reaction

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Ar/H₂/O₂‐Controlled Growth Thermodynamics and Kinetics to Create Zero‐, One‐, and Two‐Dimensional Ruthenium Nanocrystals towards Acidic Overall Water Splitting

The Effect of Cation Mixing in LiNiO₂ toward the Oxygen Evolution Reaction