Cristiane Barbieri Rodella

The origin of terrestrial life and ecosystems fundamentally changed the biosphere. Lichens, symbiotic fungi-algae partnerships, are crucial to nutrient cycling and carbon fixation today, yet their evolutionary history during the evolution of terrestrial ecosystems remains unclear due to a scarce fossil record. We demonstrate that the enigmatic Devonian fossil Spongiophyton from Brazil captures one of the earliest and most widespread records of lichens. The presence of internal hyphae networks, algal cells, possible reproductive structures, calcium oxalate pseudomorphs, abundant nitrogenous compounds, and fossil lipid composition confirms that it was among the first widespread representatives of lichenized fungi in Earth’s history. Spongiophyton abundance and wide paleogeographic distribution in Devonian successions reveal an ecologically prominent presence of lichens during the late stages of terrestrial colonization, just before the evolution of complex forest ecosystems.

Oxygen vacancies play a pivotal role in tailoring the electronic, optical, and catalytic properties of reducible metal oxides. Here, we provide a complete overview of oxygen vacancy-induced structural evolution of iron-doped titanium oxide nanomaterials with insights into their synthesis, formation, and crystallization processes. Structural analysis combining multiple techniques reveals the formation of anatase nanoparticles at low Fe loadings (i.e., ≤10 at. % Fe). At intermediate Fe concentrations (i.e., 15-20 at. % Fe), a mixture of anatase and rutile forms with the presence of extended disordered defects similar to crystallographic shear planes. These become more notable at high Fe loadings (i.e., ≥30 at. % Fe) with the complete transition to the rutile phase with a high density of defects. Moreover, we provide important information on the nucleation, growth, and crystallization processes during synthesis, emphasizing the impact of Fe atom incorporation on the TiO₂ lattice, the formation of reaction intermediates, and the structural evolution at the nano regime. The ability to control oxygen vacancies and engineer defects in Fe-doped TiO₂ allows for the optimization of charge transport, enhancing catalytic activity and tuning optical properties for applications in environmental remediation, sensing, and next-generation semiconductor technologies.

Synchrotron radiation X-ray diffraction facilities equipped with fast area detectors can generate X-ray diffraction (XRD) patterns in seconds. This capability is fundamental to revealing transient crystalline phases and the structural evolution of samples and devices for technology applications. However, it generates XRD patterns usually faster than the user can process during the experiment. Thus, an open-source and user-friendly software package named IGUAPE was developed for the PAINEIRA beamline (Sirius, Brazil). It allows visualization of the X-ray diffractograms as soon as the azimuthal integration of the Debye rings is processed and the XRD pattern is created. The software can also perform a single-peak qualitative analysis of the diffraction data. Upon selecting a diffraction peak in the XRD pattern, the peak position, integrated area and full width at half-maximum variation during the in situ or operando experiment are given.

The evolutionary onset of animal biomineralization in the late Ediacaran ( ca 555–538 Ma) is marked by the global appearance of enigmatic tubular fossils with unresolved phylogenetic relationships. Among these, Corumbella werneri from the Tamengo Formation (Corumbá Group, Brazil) has been variously interpreted as affiliated with cnidarians or bilaterians. Using synchrotron imaging and machine learning, we analysed new specimens of C. werneri to reconstruct their original skeletal organization. Our findings reveal that Corumbella’ s tubes were originally conico-cylindrical. Large individuals of Corumbella , including less compacted specimens, and compression experiments with modern annelid tubes all indicate that previous reconstructions of a quadrate outline and midline features were misled by taphonomic artefacts. We also show that the wall of Corumbella is composed of a single layer of ring-shaped elements. Unlike the fourfold symmetry of scyphozoans or the complex cataphract-like structures of Cambrian bilaterians (e.g. halkieriids, tommotiids and wiwaxiids), Corumbella displays structural similarities with other late Ediacaran corumbellomorphs, such as Costatubus . These taxa exhibit a distinctive barrel-on-barrel tube construction, with modular elements stacked on each other rather than nested. Our findings redefine Corumbella ’s morphology and phylogenetic affinities, contributing to a broader understanding of early biomineralizing metazoans and their ecological roles in the Ediacaran biosphere.

Oxygen vacancies play a pivotal role in tailoring electronic, optical, and catalytic properties of reducible metal oxides. Here, we provide a complete overview of oxygen vacancy-induced structural evolution of iron-doped titanium oxide nanomaterials with insights into their synthesis, formation, and crystallization processes. Structural analysis combining multiple techniques reveals the formation of anatase nanoparticles at low Fe loadings (i.e., ≤ 10 at. % Fe). At intermediate Fe concentrations (i.e., 15-20 at. % Fe), a mixture of anatase and rutile forms with the presence of extended disordered defects similar to crystallographic shear planes. These become more notable at high Fe loadings (i.e., ≥ 30 at. % Fe) with the complete transition to the rutile phase with a high density of defects. Moreover, we provide important information on the nucleation, growth, and crystallization processes during synthesis, highlighting the impact of Fe atoms incorporation on the TiO2 lattice, the formation of reaction intermediates, and the structural evolution at the nano regime. The ability to control oxygen vacancies and engineer defects in Fe-doped TiO2 opens new possibilities for optimizing charge transport, enhancing catalytic activity, and tuning optical properties for applications in environmental remediation, sensing, and next-generation semiconductor technologies.

The search for alternative sources of, and substitutes for, chemicals derived from fossil-based feedstocks encourages studies of heterogeneous catalysts to increase the feasibility of sustainable production of biomass derivatives, such as γ-valerolactone, among others. In this context, first, the performance of a titania-supported nickel catalyst (a non-noble catalyst) was evaluated in the reaction of hydrogenation of levulinic acid to γ-valerolactone in water using molecular hydrogen. The methods used included the synthesis of titania via the solgel method and nickel deposition by deposition–precipitation via removal of the complexing agent. The nickel was activated in a flow of hydrogen; the temperature of reduction and the calcination step were investigated with experiments at reaction conditions to study the catalyst’s stability. Then, after a statistical evaluation of several proposed kinetic models, the kinetics of the reaction was found to be best represented by a model obtained considering that the reaction over the surface was the determinant step, followed by the non-dissociative adsorption of hydrogen and the competitive adsorption among hydrogen, levulinic acid, and γ-valerolactone. With that model, the activation energy of the levulinic acid to 4-hydroxypentanoic acid step was (47.0 ± 1.2) kJ mol⁻¹, since the determinant step was the hydrogenation reaction of the levulinic acid to 4-hydroxypentanoic acid. It was also concluded that the catalyst prepared was stable, active, and selective to γ-valerolactone.

The design and tuning of active sites (e.g., metallic, acid, and redox sites) are crucial for developing active, selective, and stable catalysts. Metal-support interactions (MSI) and the creation of interfacial sites can tailor the catalytic performance of metal/oxide catalysts for various reactions, directly impacting C-O, C-C, and C-H bond activation and H2 spillover. By modulating the acidity of the support (i.e., Brønsted-rich or Lewis-rich), we elucidate the role of acid sites over the acetone hydrodeoxygenation reaction pathways. Brønsted-rich catalysts favor the formation of selective C-O bond cleavage products, whereas Lewis-rich catalysts favor C-C coupling + C-O bond cleavage cascade products. We demonstrate that tailoring active sites from the support and constructing active metal-oxide interfacial sites can tune the catalytic performance toward targeted reaction pathways with enhanced stability. Our findings provide insights into C-O, C-C, and C-H bond activation, cleavage, and coupling that can be expanded to multiple catalytic reactions, contributing to the development of new functional materials with enhanced performance.

Controlling the shape and size dispersivity and crystallinity of nanoparticles (NPs) has been a challenge in identifying these parameters' role in the physical and chemical properties of NPs. The need for reliable quantitative tools for analyzing the dispersivity and crystallinity of NPs is a considerable problem in optimizing scalable synthesis routes capable of controlling NP properties. The most common tools are electron microscopy (EM) and X-ray scattering techniques. However, each technique has different susceptibility to these parameters, implying that more than one technique is necessary to characterize NP systems with maximum reliability. Wide-angle X-ray scattering (WAXS) is mandatory to access information on crystallinity. In contrast, EM or small-angle X-ray scattering (SAXS) is required to access information on whole NP sizes. EM provides average values on relatively small ensembles in contrast to the bulk values accessed by X-ray techniques. Besides the fact that the SAXS and WAXS techniques have different susceptibilities to size distributions, SAXS is easily affected by NP–NP interaction distances. Because of all the variables involved, there have yet to be proposed methodologies for cross-analyzing data from two techniques that can provide reliable quantitative results of dispersivity and crystallinity. In this work, a SAXS/WAXS-based methodology is proposed for simultaneously quantifying size distribution and degree of crystallinity of NPs. The most reliable easy-to-access size result for each technique is demonstrated by computer simulation. Strategies on how to compare these results and how to identify NP–NP interaction effects underneath the SAXS intensity curve are presented. Experimental results are shown for cubic-like CeO₂ NPs. WAXS size results from two analytical procedures are compared, line-profile fitting of individual diffraction peaks in opposition to whole pattern fitting. The impact of shape dispersivity is also evaluated. Extension of the proposed methodology for cross-analyzing EM and WAXS data is possible.

This study combines operando XRD & Raman spectroscopy and DFT simulation to reveal how Li₂CO₃ formation and reversibility may contribute to energy storage in supercapacitors.