Articles publicats en revistes (Institut de Nanociència i Nanotecnologia (IN2UB))

URI permanent per a aquesta col·leccióhttps://hdl.handle.net/2445/59249

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Including nanoparticle shape into macrospin models
(American Physical Society, 2026-07-20) López-Vázquez, Iago; Iglesias, Òscar; Serantes, David
We investigate the feasibility of the macrospin approximation to account for the actual shape of soft magnetic nanoparticles (MNPs) with realistic geometries. Specifically focusing on magnetite, we use the superellipsoidal parametrisation to account for a variety of shapes, with a continuous interpolation from spherical to cubic morphologies, as well as different elongations. Our procedure consists of the direct comparison between angular-dependent hysteresis loops obtained by full micromagnetic simulations, with those produced by an extended Stoner-Wohlfarth (SW) model that incorporates both the intrinsic cubic magnetocrystalline anisotropy, and an effective uniaxial contribution arising from the particle elongation. The limits of validity of the macrospin description are approximately 10-60 nm for axial ratios r>1.5, and 20-60 nm for 1.0.
Interfacially regulated hierarchical Ni-based electrodes for selective electrocatalytic hydrogenation of biomass-derived platform molecules
(Elsevier B.V., 2026-11-15) Vilariño Casaus, Pol; Gómez, Elvira; Serrà i Ramos, Albert; Tayyebi, Ebrahim; Exner, Kai S.; Montemo, Fatima
Electrocatalytic hydrogenation of biomass-derived oxygenates is limited by hydrogen evolution, acid-driven degradation of non-noble electrodes, and poor control of gas-evolving interfaces. Hierarchical Ni electrodes were prepared by dynamic hydrogen bubble templating on semiporous stainless steel and coupled with dodecyltrimethylammonium chloride (DTAC) interfacial regulation and Ru decoration. The macroporous, dendritic scaffold supports surface accessibility, reactant transport, and gas release, while DTAC attenuates unproductive proton reduction and improves structural persistence in acidic media. The platform was evaluated for levulinic acid (LA), 5-hydroxymethylfurfural (HMF), and furfural (FF), showing reactant-dependent selectivity. LA reduction was strongly temperature-dependent: 4-hydroxypentanoic acid-rich mixtures dominated at 5 °C, whereas γ-valerolactone (GVL) was favored at 50 °C, reaching 95.8% conversion, 88.7% Faradaic efficiency, and 92.6% GVL selectivity on DTAC-modified Ru-Ni A. HMF mainly yielded 2,5-bis(hydroxymethyl)furan, while FF gave furfuryl alcohol. Density functional theory calculations on clean Ni facets provide qualitative mechanistic context for possible surface-bound LA-to-GVL pathways and their sensitivity to surface geometry and reaction sequence.
Revealing the spin structure, exchange constants and local anisotropy in nanoparticles with polarised neutron powder diffraction: Mn3O4 as case study
(Elsevier, 2026-10-01) Kibalin, Iurii; Gukasov, Arsen; Golosovsky, Igor; Roca, A. G.; López-Ortega, Alberto; Estrader i Bofarull, Marta; Hansen, Thomas C.; Puente Orench, Ines; Lelièvre-Berna, Eddy; Nogués, Josep
The functional magnetic properties of nanostructured materials can be distinctly different from their bulk counterparts. Understanding these properties is crucial for basic material science and for applications using nanostructured magnetic materials. However, determining intrinsic magnetic structures, exchange constants and local magnetic anisotropy in nanoparticles poses considerable challenges. Here, polarised neutron powder diffraction (PNPD) data, analysed in the frame of the Local Susceptibility and Model Hamiltonian approaches, is used to gain information on the contribution of the different magnetic sublattices on the magnetisation process in Mn3O4 nanoparticles in unprecedented detail. The magnetic order is found to be a Yafet-Kittel-type canted structure with inter- and intra-sublattice antiferromagnetic couplings, similar to bulk. PNPD corroborates that the c-axis is the hard-axis and the individual contributions of each magnetic site to the easy-plane magnetic anisotropy are determined. Remarkably, the analysis of the PNPD data provides the foremost determination of the microscopic magnetic parameters in nanoparticles, namely, intra- and inter- sub-lattice exchange constants and the local anisotropy parameter. The obtained values are consistent with bulk Mn3O4 experimental and theoretical results. These results open the path for the use of PNPD to gain unique magnetic information in nanostructured materials, particularly in complex, novel, or poorly understood systems.
Transition metaldoped TiO₂ and CeO₂ photocatalysts modified with Ti₃C₂ MXene for PMS-driven advanced oxidation of pharmaceutical pollutants
(Elsevier B.V., 2025-09-26) Serafin, Jarosław; Bujaldón Carbó, Roger; Sreńscek-Nazzal, Joanna; Kałamagad, Agnieszka; Gómez, Elvira; Vendrell, Xavier; Serrà i Ramos, Albert
Pharmaceutical residues are increasingly persistent in aquatic environments due to their chemical stability andresistance to conventional wastewater treatment. To address this, we developed a two-step, performance-guidedsynthesis of TiO₂- and CeO₂-based photocatalysts: first doped with transition metals (Fe, Ni, Cu, Mo, Pd) andsubsequently modified with 2D Ti₃C₂ MXene to enhance peroxymonosulfate (PMS) activation under UV andvisible light. Among the dopants, Fe and Ni imparted the most favorable physicochemical features, includingnarrowed optical band gaps, increased oxygen vacancy concentrations, and reduced photogenerated chargerecombination, as evidenced by UV–vis, XPS, and photoluminescence analyses. Post-synthetic MXene integrationimproved interfacial charge separation and visible-light absorption, achieving >99 % total organic carbon (TOC)mineralization of a ternary pharmaceutical mixture (tetracycline, levofloxacin, and paracetamol) in real tapwater under UV irradiation. Comprehensive structural (XRD, Raman, TEM), optical (UV–vis DRS, PL), andsurface (XPS) characterizations identified the Ni–CeO₂–MXene composite as the most efficient, showing optimaldefect structure, redox activity, and electronic conductivity. The catalyst maintained >95 % activity over fivereuse cycles, with minimal leaching confirmed by ICP-OES. Post-reaction XPS revealed moderate surfacemodification (Ce4+/Ce3+ and Ni2+/Ni3+ ratios shift) without signs of structural degradation. Kinetic analysisconfirmed pseudo-first-order degradation with high rate constants and short half-lives, highlighting theirapplicability for rapid pharmaceutical mineralization. This study proposes a rational and selective approach forcoupling metal doping and 2D conductive interfaces, enabling the scalable design of stable and efficient photocatalystsfor PMS-driven advanced oxidation processes (AOPs) in water purification
MXenes: Multifunctional 2D materials for hydrogen evolution, energy storage, and carbon capture applications
(Elsevier B.V., 2025-11-01) Serafin, Jarosław; Chaitoglou, Stefanos; Farid, Ghulam; Ma, Y.; Dziejarski, Bartosz; Sánchez Niubò, Albert; Vendrell, Xavier; Amade Rovira, Roger
Ti₃C₂Tₓ MXene was synthesized by selective etching of Ti₃AlC₂ MAX phase using HF. Structural and surface properties were assessed via XRD, Raman, SEM, HRTEM, BET, and XPS, confirming Al removal, interlayer expansion, and functionalization with single bondF, –OH, and = O groups. The resulting MXene exhibited a specific surface area of 26.7 m2/g and pore size of 16.2 nm. A single batch was deployed in three applications: as an HER electrocatalyst in 1 M H₂SO₄, achieving −511 mV onset potential, 190 mA cm−2 at −760 mV, and a Tafel slope of 184 mV dec−1; as a supercapacitor electrode in 3 M KOH, with areal capacitance of 411.1 mF cm−2 and 86.9 % diffusion-controlled contribution; as a CO₂ adsorbent, achieving uptakes of 0.80 and 0.66 mmol g−1 at 0 °C and 25 °C, respectively. Adsorption data fitted best to the Radke–Prausnitz isotherm, indicating mixed physisorption–chemisorption. A techno-economic analysis yielded a production cost of ~2.83 €/g. These results demonstrate the multifunctionality and scalability of Ti₃C₂Tₓ MXene as a good material for hydrogen generation, energy storage, and carbon capture.
Coupling TiO2 with Nb carbide-based materials for H2 photoproduction: From 3D carbides to 2D MXenes
(Elsevier B.V., 2025) Sánchez Ruiz, Adrià; Escolano Casado, Guillermo; Bania, Margarita; Koning, Matthijs; Serafin, Jarosław; Ramírez de la Piscina, Pilar; Mino, Lorenzo; Homs Martí, Narcís
In this work we coupled 3D Nb carbide, ternary layered NbMAX, and 2D NbMXene with TiO2, developing new photocatalysts for the renewable H2 production from ethanol aqueous solutions. A new preparation method of Nb2CTx MXene is reported; the hydrothermal method proposed uses NH3(aq) and avoids the utilization of hazardous HF or a strong acid and fluoride salts. After thorough characterization of the structural and physico-chemical features of the materials, their photocatalytic performance has been related to their photoelectrochemical properties. Moreover, the interaction of the reactant molecules with the TiO2-based composites and their evolution under UV irradiation has been investigated by in situ IR spectroscopy. All composites showed a higher H2 production rate and a higher lifetime of photogenerated charges (h+/e-) than TiO2. The Nb2CTx-containing photocatalyst showed the best H2 production yield, both in gas and liquid phase, owing to a very efficient transfer of the photogenerated electrons from the TiO2 conduction band to the MXene phase, decreasing the rate of charge recombination and favoring the H2 formation. The H2 production of NbMXene/TiO2 was more than 3.5 times that of TiO2 and showed a stable behavior at least up to 7 h with light on/light off cycles.
Silicon-based nanopillars: a novel platform for tissue applications
(Royal Society of Chemistry, 2025-12-21) Piergallini, Cristiano ; Díaz Valdivia, Natalia; Deyà, Alba; Fernández Nogueira, Patricia; Singh, Rahul ; Bertelsen, Christian Vinther; Svendsen, Winnie Edith; Corominas, Montserrat (Corominas Guiu); Gombau, Lourdes ; Sanz Fraile, Héctor; Reguart, Noemí; Romano Rodríguez, Albert; Serras Rigalt, Florenci; Luna, Noemí de ; Alcaraz Casademunt, Jordi; Ollé Monge, Marta
Nanostructured surfaces are increasingly used for cell applications due to their enhanced interactions with numerous cell types; yet, their effects on tissues remain unexplored. To address this limitation, we designed vertical silicon nanopillar (Si-NP) arrays with high density, high aspect ratio and submicrometer diameter, as an optimized geometry based on previous cell-nanostructure studies. Using state-of-the-art in vitro and ex vivo assays, we examined adhesion and biocompatibility of biological samples of different origin and level of complexity -human epithelial-like cell lines, Drosophila imaginal discs and patient-derived lung cancer biopsies-laid on Si-NP arrays or unpatterned flat Si surfaces. Our results demonstrated that Si-NP arrays significantly improved cell and tissue adhesion while preventing oxidative damage and early apoptosis. Consistently, focused ion beam-scanning electron microscopy imaging of cells and tissues showed extended horizontal protrusions and limited vertical wrapping around Si-NP, revealing enhanced cell-NP interactions without cell/tissue penetration. In contrast, flat Si surfaces showed poor adhesion, increased apoptosis, and failed to support tumor biopsy attachment. Interaction with Si-NP arrays upregulated reactive oxygen species (ROS), yet mitochondria-associated ROS remained unchanged, and consequently apoptosis was not induced, indicating that the increased ROS arose from non-mitochondrial compartments and did not compromise viability. Notably, Si-NP arrays matched or outperformed biological responses on tissue culture plastic and Transwell-based assays, which are common in vitro and ex vivo substrates, respectively. These findings provide the first demonstration of the biological suitability of Si-NP arrays for tissue applications in research and clinical translation.
Tracking Microhydration of the NaCl Rocksalt Molecule by Quantum Chemical Calculations and Penning Ionization Electron Spectroscopy in Helium Nanodroplets
(Wiley-VCH, 2026-05-01) Pi Pericay, Martí; Barranco Gómez, Manuel; Ltaief, LB; Sishodia, Keshav; Richter, Robert; Eloranta, Jussi; Krishnan, Sivarama; Calvo, Florent; Mudrich, Marcel
The microhydration of rock salt (NaCl) molecules was investigated theoretically by density-functional theory and force field calculations and experimentally by high-resolution Penning ionization electron spectroscopy (PIES) in helium nanodroplets. The calculations reveal a transition from contact ion pair structures to solvent-separated ion pairs at n = 12–15. However, it takes n % 17 water molecules to form a complete solvation shell around the Cl− anion and as many as n % 34 to fully hydrate the Na+ cation, thus the entire NaCl molecule. Although NaCl molecules are predicted to be fully submerged inside the droplets, the PIES of NaCl are highly resolved, in stark contrast to other molecular species. Codoping the droplets with a controlled number of n = 1–10 water molecules leads to efficient quenching of the NaCl Penning ionization signal and to its full suppression for n ≳ 30, in line with the calculations.
Decoding Solvent Effects in Electrocatalytic Biomass Valorization: Levulinic Acid to γ-Valerolactone
(American Chemical Society, 2026-04-08) Vilariño Casaus, Pol; Bautista, Queralt; Gómez, Elvira; Serrà i Ramos, Albert
Electrocatalytic hydrogenation (ECH) of biomass-derived levulinic acid (LA) offers a sustainable route to prepare γ-valerolactone (GVL), a versatile green solvent and fuel additive. Yet despite its promise, most studies overlook the decisive role of the solvent environment, conflating conversion with true product yield. Here we disentangle these effects by systematically probing LA reduction over GC, Cu, Ni, and CuNi cathodes in three contrasting solvents (MeOH, DMSO, IPA) at two temperatures (15 and 35 °C). A clear design rule emerges: the solvents dictate the conversion ceiling, while temperature gates selectivity. At 15 °C, LA consumption is observed but productive lactonization toward GVL remains “off”, yielding only traces of HVA. At 35 °C, lactonization is unlocked, enabling GVL selectivity’s >90% in MeOH with metal-earth-abundant, Ni-based catalysts. Solvent characterization (viscosity, dielectric constant, ionic conductivity) combined with DFT analysis provides a direct rationale for the experimental trends. Methanol emerges as the most effective medium, consistent with its low viscosity and high electrolyte conductivity, which together mitigate diffusion and iR penalties relative to IPA and DMSO. DMSO shows intermediate performance, consistent with strong solvation/dielectric stabilization of intermediates, whereas IPA combines high viscosity and low ionic mobility, leading to the lowest conversions. Overall, efficient LA-to-GVL ECH is not dictated by conversion alone but by the coupled interplay of solvent properties, catalyst identity, and temperature required to link surface hydrogenation with thermally assisted lactonization.
Solar photo-thermocatalytic valorization of biomass waste to biofuel precursors using inexpensive Ni–P/graphite catalysts
(Elsevier B.V., 2026-10-01) Rigual Miret, Jordi; Fons, Arnau; Nogués, Josep; Esplandiu, María J.; Gómez, Elvira; Sepúlveda, Borja; Serrà i Ramos, Albert
Developing efficient, low-cost catalytic routes for biomass upgrading for sustainable fuel and chemical production is a crucial step toward a greener society and circular economy. Ni–P/graphite catalysts prepared by electroless deposition on graphite microflakes were used for photo-thermocatalytic transfer hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) in isopropanol, without external H2 or noble metals. Graphite provides broadband optical absorption and localized heat generation; the Ni–P coating supplies the active hydrogen-transfer sites, with isopropanol serving as hydrogen donor. Under near-infrared laser irradiation at 105 °C, complete LA conversion was achieved in 120 min, 2.5-fold faster than the solvothermal process at the same temperature. Solar-driven tests using a parabolic concentrator (105 °C, 2.5 mg mL−1, 100 mL scale) yielded 99.1% GVL after 80 min; over-reduction to valeric acid became significant only at 120 min. The catalyst retained near-quantitative activity over five consecutive cycles with negligible cumulative Ni and P leaching. Tests with a synthetic biomass hydrolysate approximating wheat-derived acid hydrolysate composition (LA/furfural/formic acid, 104:1:36 M ratio) showed LA conversion exceeding 99.9% at 40 min and complete furfural conversion by 80 min. The furfural hydrogenation network yielded furfuryl alcohol, 2-methylfuran, tetrahydrofurfuryl alcohol, and 2-methyltetrahydrofuran (23.2% at 120 min). Formic acid decomposition supplemented isopropanol as hydrogen donor under mixed-feed conditions. The optimal catalyst loading of 2.5 mg mL−1 was 36-fold lower than the Raney Ni dose required for comparable photo-thermocatalytic LA conversion, which additionally demanded a reaction temperature of ca. 130 °C.
Bioinspired hierarchical electrospun TiO2/BiOI nanofibers for multifunctional photocatalytic PMS activation: Antibiotics and microplastics removal
(Elsevier Ltd., 2026-10) Huidobro, Laura; Abid, Mahmoud; Bechelany, Mikhael; Gómez, Elvira; Serrà i Ramos, Albert
Emerging antibiotics and microplastics are poorly removed by conventional treatment processes, requiring oxidation processes that address both dissolved and particulate contaminants. Hierarchical electrospun TiO2/BiOI nanofibers (TBO1–TBO4; BiOI growth 2–16 h) were engineered for photocatalytic peroxymonosulfate (PMS) activation under UV-A (365 nm) and visible light. At pH 7 and 20 °C (sulfamethoxazole, SMX, 5 ppm; catalyst 0.50 g L−1; PMS 2.5 mM), TBO3 achieved near-complete, blank-corrected total organic carbon (TOC) removal (≥99%) in 120 min under visible light + PMS. For a four-component multipollutant solution (20 ppm total), TBO3 reached near-complete TOC removal after blank correction (reported as ≥99%, with residual TOC close to the method quantification limit) in 120 min and maintained activity over nine cycles under visible light + PMS (≤0.7 %age-point change; leaching below detection), whereas UV-A + PMS decreased to 85.3% by cycle 9 with ppb-level leaching. Quenching and probe assays indicate a radical-accessible PMS-assisted oxidation network; strong suppression by tert-butanol and methanol supports major •OH-accessible oxidation with a sulfate-radical-type contribution. Under visible light (465–470 nm) + PMS, cross-linked polystyrene (PS) microplastics (20 ppm solids) underwent surface erosion, cracking, delamination, and fragmentation, accompanied by release of dissolved/sub-10 μm carbonaceous products in scaled-up tests, supporting partial oxidative transformation of particulate microplastics.
SmartTrap: automated precision experiments with optical tweezers
(Nature Publishing Group, 2026-06-18) Selin, Martin; Ciarlo, Antonio; Pesce, Guiseppe; Bengtsson, Lars; Camunas-Soler, Joan; Sundar Rajan, Vinoth; Westerlund, Fredrik; Wilhelmsson, L. Marcus; Pastor, I. (Isabel); Ritort Farran, Fèlix; Smith, Steven B.; Bustamante, Carlos; Volpe, Giovanni
Optical tweezers are widely used in single-molecule biophysics, cell biomechanics and soft matter physics, but require a human operator, limiting throughput and repeatability. Here we present a smart optical tweezers platform, named SmartTrap, capable of performing complex experiments autonomously by integrating real-time three-dimensional particle tracking, custom electronics and a microfluidics system. Through a series of experiments, we demonstrate it can operate continuously, acquiring high-precision data over extended periods of time. By bridging the gap between manual experimentation and autonomous operation, SmartTrap establishes a robust and open-source framework for the next generation of optical tweezers research, capable of performing large-scale studies in single-molecule biophysics, cell mechanics and colloidal science with minimal experimental overhead and operator bias.
SiC-Based MIS gas sensor for high water vapor environments
(Elsevier, 2011) Casals Guillén, Olga; Becker, Th.; Godignon, P.; Romano Rodríguez, Albert
In this work we will prove that SiC-based MIS capacitors can work in environments with extremely high concentrations of water vapor and still be sensitive to hydrogen, CO and hydrocarbons, making these devices suitable for monitoring the exhaust gases of hydrogen or hydrocarbons based fuel cells. Under the harshest conditions (45% of water vapor by volume ratio to nitrogen), Pt/TaOx/SiO2/SiC MIS capacitors are able to detect the presence of 1 ppm of hydrogen, 2 ppm of CO, 100 ppm of ethane or 20 ppm of ethene, concentrations that are far below the legal permissible exposure limits.
An LED Platform for Micropower Gas Sensors
(MDPI, 2018-11-30) Markiewicz, Nicolai; Casals Guillén, Olga; Fàbrega Gallego, Cristian; Wasisto, Hutomo Suryo; Waag, Andreas; Prades García, Juan Daniel
We developed an integrated platform to build up conductometric sensors with controlled illumination. Our device contains a miniaturized indium gallium nitride (InGaN) LED as a light source, and a set of interdigitated electrodes (IDEs) in close contact with the LED. The sensor material is later deposited on top of the IDE, to monitor its resistance. In this configuration, all the light emitted by the LED is collected by the sensor material, leading to a very efficient photoexcitation. We demonstrate the effectiveness of the approach building a photoactivated gas sensor based on ZnO operating with as little as 100 μW.
Universal cold RNA phase transitions
(National Academy of Sciences, 2024-08-16) Rissone, Paolo; Severino, Aurélien; Pastor, I. (Isabel); Ritort Farran, Fèlix
RNA’s diversity of structures and functions impacts all life forms since primordia. We use calorimetric force spectroscopy to investigate RNA folding landscapes in previously unexplored low-temperature conditions. We find that Watson–Crick RNA hairpins, the most basic secondary structure elements, undergo a glass-like transition below TG ∼ 20 ◦C where the heat capacity abruptly changes and the RNA folds into a diversity of misfolded structures. We hypothesize that an altered RNA biochemistry, determined by sequence-independent ribose–water interactions, outweighs sequence-dependent base pairing. The ubiquitous ribose–water interactions lead to universalRNA phase transitions below TG, such as maximum stability at TS ∼ 5 ◦C where water density is maximum, and cold denaturation at TC ∼ −50 ◦C. RNA cold biochemistry may have a profound impact on RNA function and evolution.
Robust calibration method for polarization cameras integrated with chromatic retarders
(Optical Society of America, 2025-07-28) Li, Huihui; Bian, Subiao; Arteaga Barriel, Oriol
Polarization cameras provide a compact and efficient solution for real-time polarization imaging but suffer from chromatic calibration errors when used in combination with wavelength-dependent optical components such as linear retarders. In this work, we introduce an analytical calibration method specifically designed for polarization cameras integrating chromatic retarders, which can be used both in monochromatic and color sensors. This method algebraically accounts for spectral averaging and depolarization effects arising from wavelength-dependent retardance, enabling robust and accurate polarization calibration across different spectral channels. The approach is experimentally validated using a commercial color polarization camera (FLIR Blackfly S) with integrated RGB Bayer filters and micro-polarizers, along with broadband illumination sources. Experimental results demonstrate that the effective spectral parameters, such as the effective wavelength and spectral bandwidth obtained by our calibration method, are close to theoretical predictions.
Tuning luminescence in gold(I)-phosphine complexes: structural, photophysical, and theoretical insights
(Royal Society of Chemistry, 2025-01-22) Atencio, P. Anyie; Burguera, Sergi; Zhuchkov, George; Aquino Samper, Araceli de; Ward, Jas S.; Rissanen, Kari; Lima, João Carlos; Angurell Purroy, Inmaculada; Frontera, Antonio; Rodríguez Raurell, Laura
Gold(I) complexes featuring phosphine ligands functionalized with chromophores such as triphenylene, phenanthrene, and carbazole were synthesized and systematically studied to explore the relationship between molecular structure and luminescence properties. Comprehensive photophysical characterization revealed that the coordination environment and chromophore positioning significantly influence intersystem crossing, phosphorescence, and aggregation behavior. In solution, aggregation-induced phenomena were probed using computational tools, including density functional theory (DFT) and noncovalent interaction (NCI) analysis, revealing diverse π-stacking and Au⋯π interactions. Distinct photophysical trends were identified among the three series of compounds, with triphenylene derivatives exhibiting aggregation-induced emission broadening and phenanthrene derivatives showing strong heavy atom effects. The combination of experimental and theoretical insights provides a foundation for designing luminescent materials with tunable properties for optoelectronic applications.
Optimizing energy storage: Carbon implantation in NiO matrix unveils C–NiO's hybrid capacitive and battery-like behavior with enhanced electrochemical performance
(Elsevier B.V., 2024-03-19) Shafique, Muhammad Ahsan; Farid, Ghulam; Shaheen, Fozia; Zaheer, Zeeshan; Murtaza, Ghulam; Sharif, Sadia; Ahmad, Riaz
Doping is a common strategy employed to enhance material properties. Numerous researchers have introduced carbon into the nickel oxide (NiO) matrix through various methods to improve the electrochemical performance for energy storage applications. This study investigates the impact of carbon implantation into the NiO matrix using a particle accelerator. Cyclic voltammetry profiles of carbon-implanted NiO (C–NiO) reveal distinct oxidation–reduction peaks, and one side of the CV curves exhibits a rectangular shape, confirming the hybrid capacitive and battery-like behavior of C–NiO. The reduced separation between oxidation–reduction peaks and the increased specific capacitance at higher scan rates validate the capacitive nature of C–NiO. Enhanced electrochemical performance was further explored through GCD, EIS, and BET techniques. C–NiO demonstrates impressive capacitance retention of 93.8 % after 5000 cycles. The Nyquist plot indicates that the improved performance of C–NiO is attributed to its heightened electrode activity, resulting from lower charge-transfer resistance. BET analysis confirms that C-doping leads to a larger surface area. In the NiO matrix, two bands of adsorbed CO2 are observed, whereas these bands are absent in C–NiO, indicating clearer pathways for ion–electron exchange. Compared to undoped NiO (55 F/g at 50 mV/s), C–NiO exhibits a more than tenfold increase in specific capacitance (1079 F/g at 50 mV/s).
Rapid and simple dual extraction for the analysis of lipids and autoantigenic peptides within phosphatidylserine-liposomes
(Elsevier B.V., 2024-08-13) El Ouahabi, Oumaima; Mancera Arteu, Montserrat; Latorre, Irene; Salvadó, Míriam; Rodríguez-Vidal, Sílvia; Sanz Nebot, María Victoria
Autoimmune diseases are a major health concern in developed countries. Currently, only palliative treatments based on anti-inflammatories and immunosuppressors are available. A novel antigen-specific therapy that uses a physiological process of tolerance generation is being developed. This is plausible by using phosphatidylserine rich liposomes (PS-liposomes), which bio-mimic apoptotic cells, encapsulated with the autoantigen responsible of generating the autoimmunity. In this way, tolerance against the own cells or tissues that were considered hostile can be achieved. In addition, only by changing the encapsulated peptide, different autoimmune diseases can be treated. Efficacy of this approach was demonstrated in type I diabetes, rheumatoid arthritis, multiple sclerosis, and myasthenia gravis. In the regulatory pre-clinical phase, analytical methodologies to evaluate the quality of the product need to be developed. In this regard, identification and quantification of the encapsulated peptide and lipids are considered critical quality attributes. In this study, a rapid and simple liquid–liquid extraction procedure, based on Bligh-Dyer method, is described for dual extraction of peptides and lipids within PS-liposomes formulation. This single step allows the separation of lipids and the encapsulated peptide in two different phases. For the subsequent analysis, two different HPLC methods were developed. The organic phase, which contains the lipids was analysed by HPLC-ELSD, while the aqueous phase, containing the encapsulated peptide, was analysed by HPLC-UV. Both methods were also validated in terms of accuracy, precision, linearity, LOD and LOQ. The extraction procedure has demonstrated highly efficient separation of lipids and peptides, avoiding interferences between them in the quantification.
Enhanced Selective Contact Behavior in a-Si:H/oxide Transparent Photovoltaic Devices via Dipole Layer Integration
(Wiley-VCH, 2024-06-14) López García, Alex; Álvarez Suárez, Gustavo; Ros Rahola, Emilio; Ortega Villasclaras, Pablo Rafael; Voz Sánchez, Cristóbal; Puigdollers i González, Joaquim; Pérez Rodríguez, Alejandro
Transparent photovoltaic (TPV) devices have the potential to revolutionize photovoltaic (PV) technology by enabling on-site generation while minimizing visual impact. However, a major challenge in the development of TPV, as well as for many PV technologies, is the open-circuit voltage (Voc) deficit, which limits their efficiency. In this work, the development of wide-bandgap inorganic-based TPV devices is reported with a focus on low-cost, earth-abundant, stable, and nontoxic materials. The device structure consists of an ultrathin hydrogenated amorphous silicon (a-Si:H) absorber and metal-oxide layers as selective contacts. Herein, novel approach is presented to significantly improve device performance, especially in Voc, by introducing molecular dipoles in the device electron transport layer. By incorporating polyethyleneimine or poly(amidoamine) G1 and G2 dipoles, Voc (from 410 mV up to 638 mV) is significantly increased without sacrificing the average photopic transmittance of the device, leading to a record efficiency for this particular approach in TPV. Measurements confirm excellent long-term stability. This approach can potentially allow tuning the work function of the selective contacts enabling the use of low-cost, earth-abundant materials that are not optimized for a particular absorber. Furthermore, this solution circumvents the issue of low Voc by a simple interface treatment.

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