Staff directory Emma Gómez Maza

Emma Gómez Maza

Competitive Funding Officer
emma.gomez(ELIMINAR)@icn2.cat
Competitive Funding Department

Publications

2020

  • Highly reduced ecotoxicity of ZnO-based micro/nanostructures on aquatic biota: Influence of architecture, chemical composition, fixation, and photocatalytic efficiency

    Serrà A., Zhang Y., Sepúlveda B., Gómez E., Nogués J., Michler J., Philippe L. Water Research; 169 (115210) 2020. 10.1016/j.watres.2019.115210.

    Developing efficient sunlight photocatalysts with enhanced photocorrosion resistance and minimal ecotoxicological effects on aquatic biota is critical to combat water contamination. Here, the role of chemical composition, architecture, and fixation on the ecotoxicological effects on microalgae of different ZnO and ZnO@ZnS based water decontamination photocatalysts was analyzed in depth. In particular, the ecotoxicological effects of films, nanoparticles and biomimetic micro/nano-ferns were carefully assessed by correlating the algae's viability to the Zn(II) release, the photocatalyst–microalgae interaction, and the production of reactive oxygen species (ROS). The results showed a drastic improvement in algal viability for supported ZnO@ZnS core@shell micro/nanoferns, as their ecotoxicity after 96 h light exposure was significantly lower (3.7–10.0% viability loss) compared to the ZnO films (18.4–35.5% loss), ZnO micro/nanoferns (28.5–53.5% loss), ZnO nanoparticles (48.3–91.7% loss) or ZnO@ZnS nanoparticles (8.6–19.2% loss) for catalysts concentrations ranging from 25 mg L−1 to 400 mg L−1. In particular, the ZnO@ZnS micro/nanoferns with a concentration of 400 mg L−1 exhibited excellent photocatalytic efficiency to mineralize a multi-pollutant solution (81.4 ± 0.3% mineralization efficiency after 210 min under UV-filtered visible light irradiation) and minimal photocorrosion (<5% of photocatalyst dissolution after 96 h of UV-filtered visible light irradiation). Remarkably, the ZnO@ZnS micro/nanoferns showed lower loss of algal viability (9.8 ± 1.1%) after 96 h of light exposure, with minimal reduction in microalgal biomass (9.1 ± 1.0%), as well as in the quantity of chlorophyll-a (9.5 ± 1.0%), carotenoids (8.6 ± 0.9%) and phycocyanin (5.6 ± 0.6%). Altogether, the optimized ZnO@ZnS core@shell micro/nanoferns represent excellent ecofriendly photocatalysts for water remediation in complex media, as they combine enhanced sunlight remediation efficiency, minimal adverse effects on biological microorganisms, high reusability and easy recyclability. © 2019 Elsevier Ltd


2019

  • Highly active ZnO-based biomimetic fern-like microleaves for photocatalytic water decontamination using sunlight

    Serrà A., Zhang Y., Sepúlveda B., Gómez E., Nogués J., Michler J., Philippe L. Applied Catalysis B: Environmental; 248: 129 - 146. 2019. 10.1016/j.apcatb.2019.02.017. IF: 14.229

    Here we present the highly enhanced sunlight photocatalytic efficiency and photocorrosion resistance of biomimetic ZnO-modified micro/nanofern fractal architectures, which are synthesized by using a novel, simple, inexpensive and green electrochemical deposition approach in high stirring conditions. Such fern-like hierarchical structures simultaneously combine enhanced angle independent light trapping and surface/bulk modifications of the ZnO morphology to drastically increase: i) the light trapping and absorption in the visible near-infrared range, and ii) the surface to volume ratio of the architecture. This combination is crucial for boosting the sunlight photocatalytic efficiency. To modulate the electronic properties for extending the operation of the ZnO photocatalysts into the visible domain we have used three different modification approaches: sulfidation (leading to a ZnS shell), Ag decoration, and Ni-doping. The different ZnO-modified bioinspired fern-like fractal structures have been used to demonstrate their efficiency in the photodegradation and photoremediation of three different persistent organic pollutants –methylene blue, 4-nitrophenol, and Rhodamine B – under UV light, simulated and natural UV-filtered sunlight. Remarkably, the ZnO@ZnS core@shell structures exhibited an outstanding photocatalytic activity compared to the pristine ZnO catalyst, with over 6-fold increase in the pollutant degradation rate when using solar light. In fact, the catalytic performance of the ZnO@ZnS micro/nanoferns for the photoremediation of persistent organic pollutants is comparable to or better than the most competitive state-of-the-art ZnO photocatalysts, but showing a negligible photocorrosion. Ag-decorated ZnO, and Ni-doped ZnO exhibited similar excellent visible-sunlight photodegradation efficiency. Although the Ni-doped photocatalysts showed a relatively poor photocorrosion resistance, it was acceptable for Ag-decorated ZnO. Therefore, the easy fabrication and the capacity to drastically enhance the sunlight photocatalytic efficiency of the ZnO@ZnS bioinspired micro/nanoferns, together with their practically negligible photocorrosion and simple recyclability in terms of non-catalyst poisoning, makes them very promising photocatalysts for water remediation. © 2019 Elsevier B.V.


2016

  • Effective ionic-liquid microemulsion based electrodeposition of mesoporous Co-Pt films for methanol oxidation catalysis in alkaline media

    Serrà A., Gómez E., Golosovsky I.V., Nogués J., Vallés E. Journal of Materials Chemistry A; 4 (20): 7805 - 7814. 2016. 10.1039/c6ta02035f. IF: 8.262

    Pt-based direct methanol fuel cells are attracting increasing interest as environmentally friendly alternative energy sources. However, the high price of Pt and the difficulty to prepare favourable morphologies for catalysis (e.g., mesoporous materials) are hampering their development into feasible products. Here, we demonstrate a novel approach to efficiently grow mesoporous films of Pt-poor alloys (Co3Pt and CoPt3), based on electrodeposition in ionic liquid-in-water (IL/W) microemulsions. The high proportion of the electrolytic aqueous solution in the IL/W microemulsion favors a significant deposition rate, while the presence of IL drops induces the formation of highly mesoporous films. The mesoporous alloys, with pores in the 8-11 nm range, exhibit excellent durability in acidic and alkaline aggressive media, maintaining their peculiar morphology. The structures are very efficient for the catalysis of methanol electro-oxidation in alkaline media, with minimal poisoning of the catalysts. These results pave the way to develop simple, versatile environmentally friendly fuel cell catalysts to commercialize new viable ecological alternative energy sources. © 2016 The Royal Society of Chemistry.