Journal: Journal of Materials Chemistry A

Abbreviation

J. Mater. Chem. A

Publisher

Royal Society of Chemistry

Journal Volumes

ISSN

2050-7488
2050-7496

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Filters

2013 - 2019622020 - 202532
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Publications 1 - 10 of 94
  • Evolution of porosity in carbide-derived carbon aerogels
    Item type: Journal Article
    Oschatz, M.; Nickel, W.; Thommes, M.; et al. (2014)
    Journal of Materials Chemistry A
  • Heterostructure formation from hydrothermal annealing of preformed nanocrystals
    Item type: Journal Article
    Mendonça, Vagner R. de; Dalmaschio, Cleocir J.; Leite, Edson R.; et al. (2015)
    Journal of Materials Chemistry A
  • SnP nanocrystals as anode materials for Na-ion batteries
    Item type: Journal Article
    Liu, Junfeng; Wang, Shutao; Kravchyk, Kostiantyn V.; et al. (2018)
    Journal of Materials Chemistry A
  • Direct evidence of cobalt oxyhydroxide formation on a La0.2Sr0.8CoO3 perovskite water splitting catalyst
    Item type: Journal Article
    Boucly, Anthony; Artiglia, Luca; Fabbri, Emiliana; et al. (2022)
    Journal of Materials Chemistry A
    Understanding the mechanism of the oxygen evolution reaction (OER) on perovskite materials is of great interest for the development of more active catalysts. Despite a lot of literature reports, the complexity of catalytic systems and scarce in situ and operando surface sensitive spectroscopic tools render the detection of active sites and the understanding of reaction mechanisms challenging. Here, we carried out and compared in situ and ex situ ambient pressure X-ray photoelectron spectroscopy experiments on a La0.2Sr0.8CoO3-delta perovskite OER catalyst. The experimental results show that segregated surface strontium, which is present in the as prepared sample, is leached into the electrolyte after immersion, leading to surface cobalt active site enrichment. Such a cobalt-enriched oxide surface evolves into a new phase, whose spectral feature is detected in situ and after the OER. With the help of theoretical simulations, such a species is assigned to cobalt oxyhydroxide, providing direct evidence of its formation and surface segregation during the oxygen evolution reaction.
  • Reactive stability of promising scalable doped ceria materials for thermochemical two-step CO2 dissociation
    Item type: Journal Article
    Jacot, Roger; Naik, J. Madhusudhan; Moré, René; et al. (2018)
    Journal of Materials Chemistry A
  • Trends in the phase stability and thermochemical oxygen exchange of ceria doped with potentially tetravalent metals
    Item type: Journal Article
    Jacot, Roger; Moré, René; Michalsky, Ronald; et al. (2017)
    Journal of Materials Chemistry A
    Ceria is among the most prominent materials for generating clean fuels through solar thermochemical CO2 reduction and water splitting. The main optimization parameter for ceria in solar reactors is the oxygen exchange capacity (OEC, Δδ), which can be notably improved through various dopant types. Among them, tetravalent dopants excel through the formation of active vacancies which lead to particularly high OEC values. We thus performed a comprehensive screening evaluation of all dopants in the periodic table which have been reported to adopt an oxidation state of +IV. All thermally stable doped ceria samples, M0.1Ce0.9O2−δ (M = Si, Ti, V, Cr, Zr, Nb, Rh, Hf, Ta, Nb, V, Pr, and Tb), were first analyzed for Δδ improvement with thermogravimetric analysis (TGA). Dopant solubility limits and behavior in the ceria host lattice was evaluated with scanning electron microscopy (SEM-EDX) and powder X-ray diffraction techniques. No indications for carbonate side product formation were found. Hf-, Zr-, and Ta-doped ceria display higher OEC than pristine ceria, and Raman spectroscopy indicated that their improved performance is accompanied by a higher versatility in the underlying vacancy formation processes. Furthermore, the effective dopant radii are close to an optimal dopant radius around 0.8 Å for maximum Δδ according to TGA cycling experiments. These experimentally derived trends for doped ceria were supported by density functional theory (DFT) calculations which analogously correlate Δδ with the partial electronic charge of the metal dopants.
  • Unraveling two-phase transport in porous transport layer materials for polymer electrolyte water electrolysis
    Item type: Journal Article
    De Angelis, Salvatore; Schuler, Tobias; Charalambous, Margarita A.; et al. (2021)
    Journal of Materials Chemistry A
    In polymer electrolyte water electrolysis (PEWE), reducing mass-transport losses is crucial for lowering both PEWE capital and operational costs, allowing the widespread commercialization of the technology. In this work, we elucidate the complex two-phase flow (oxygen/water) developing in representative anodic porous transport layers (PTL) via operando X-ray tomographic microscopy. Thanks to a novel methodology based on the employment of stained water and a tailored data analysis pipeline, we overcome the long-standing challenge of visualizing the oxygen pathways in three dimensions in the titanium porous material, under representative operating conditions. Results show that two regions of stability develop inside the anodic PTL and the global oxygen saturation increases slightly with the increase of current density. The flow regime is found to be capillary driven and oxygen saturation is higher at the PTL/catalyst layer interface. At low current densities, oxygen pathways appear as separated clusters that merge into bigger and better-connected pathways at high current density. Analyzing the pore and water network size distributions, it is found that the oxygen phase initially occupies the bigger regions of the pore network while smaller pores are invaded at high current density. Finally, based on these findings, possible design guidelines for future better-performing PTLs are proposed.
  • Layered metal vanadates with different interlayer cations for high-rate Na-ion storage
    Item type: Journal Article
    Huang, Haijian; Tian, Tian; Pan, Long; et al. (2019)
    Journal of Materials Chemistry A
    Layer-structured metal vanadates have been regarded as promising candidates for high-rate Na-ion storage. However, without a detailed understanding of the relationship between the interlayer metal ions and the cycling performance, it remains a difficult task to systematically explore layered metal vanadates as high performance electrode materials. Herein, a series of metal vanadates with different interlayer cations such as Co2+ and Zn2+ are prepared and applied as Na-ion battery anodes. First principles simulations and ex situ X-ray diffraction measurements demonstrate that the Na-ion storage performance of the layered metal vanadates is closely related to the structural stress induced by Na+ insertion, and the ion diffusion barrier, as well as the structural reversibility. In addition, a double-interlayer-cation metal vanadate, i.e., Co0.16Zn0.09V2O5·nH2O, is reported for the first time as a high-rate Na-ion battery anode. This compound successfully combines the favorable features of Co0.25V2O5·nH2O and Zn0.25V2O5·nH2O, resulting in the best cycling performance. CV analysis and operando X-ray diffraction measurements reveal a large pseudocapacitive contribution and small volume change of Co0.16Zn0.09V2O5·nH2O during cycling. Our study presents a versatile concept for the optimization of metal vanadates for Na-ion storage, which may open a promising direction for developing high-rate energy storage materials.
  • Enhancement of the high potential specific charge in layered electrode materials for lithium-ion batteries
    Item type: Journal Article
    Robert, Rosa; Villevieille, Claire; Novák, Petr (2014)
    Journal of Materials Chemistry A
  • Origin of the increased open circuit voltage in PbS-CdS core-shell quantum dot solar cells
    Item type: Journal Article
    Speirs, M.J.; Balazs, D.M.; Fang, H.-H.; et al. (2015)
    Journal of Materials Chemistry A
Publications 1 - 10 of 94