Raul Arenal

University of Zaragoza | UNIZAR · IUI of Nanoscience of Aragon

Gaining insights into the kinetics and the thermodynamic limits of nanostructures in high-temperature reactions is crucial for controlling their unique morphology, phase, and structure. Nanotubes from lanthanide-based misfit-layered compounds (MLCs) have been known for more than a decade and were successfully produced mostly via a chemical vapor tr...

Although in situ transmission electron microscopy (TEM) of nanomaterials has been gaining importance in recent years, difficulties in sample preparation have limited the number of studies on electrical properties. Here, a support‐based preparation method of individual 1D and 2D materials is presented, which yields a reproducible sample transfer for...

The sky is the limit with regards to the societal impact nanomaterials can have on the lives. However, in this study, it is shown that their potential is out of this world. The planet Mars has an abundant source of calcium sulfate minerals and in this work, it is shown that these deposits can be the basis of transformative nanomaterials to potentia...

Imogolite nanotubes (INTs) are predicted as a unique 1D material with spatial separation of conduction and valence band edges but their large band gaps have inhibited their use as photocatalysts. The first step toward using these NTs in photocatalysis and exploiting the polarization-promoted charge separation across their walls is to reduce their b...

We show that thin layers of EuO, a ferromagnetic insulator, can be achieved by topotactic reduction under titanium of a Eu2O3 film deposited on top of a graphene template. The reduction process leads to the formation of a 7-nm thick EuO smooth layer, without noticeable structural changes in the underlying chemical vapor deposited (CVD) graphene. Th...

Chemical stability of hexagonal boron nitride (hBN) ultra-thin layers in harsh electrolytes and the availability of nitrogen site to stabilize metals like Pt are used here to develop a high intrinsic activity hydrogen evolution reaction (HER) catalyst having low loaded Pt (5 weight% or < 1 atomic%). A catalyst having non-zero oxidation state for Pt...

The sky is the limit with regards to the societal impact nanomaterials can have on our lives. However, in this study we show that their potential is out of this world. The planet Mars has an abundant source of calcium sulfate minerals and in our work, we show that these deposits can be the basis of transformative nanomaterials to potentially suppor...

Spectrally inactive, electrically insulating, chemically inert are adjectives broadly used to describe phyllosilicate minerals like mica and chlorite. Here, w e disprove the above by demonstrating aqueous suspensions of liquid exfoliated nanosheets from five bulk mica types and chlorite schist. Nanosheet quality wa s confirmed via transmission elec...

The detection of the spread of toxic gas molecules in the air at low concentration in the field requires a robust miniaturized system combined with an analytical technique that is portable and able to detect and identify the molecules, as is the case with surface enhanced Raman scattering (SERS). This work aims to address capability gaps faced by f...

The control of the magnetization inversion dynamics is one of the main challenges driving the design of new nanostructured magnetic materials for magnetoelectronic applications. Nanoparticles with onion-like architecture offer a unique opportunity to expand the possibilities allowing to combine different phases at the nanoscale and also modulate th...

Photo‐rechargeable (solar) battery can be considered as an energy harvesting cum storage system, where it can charge the conventional metal‐ion battery using light instead of electricity, without having other parasitic reactions. Here a two‐electrode lithium‐ion solar battery with multifaceted TiS2–TiO2 hybrid sheets as cathode. The choice of TiS2–...

In the present work, some MoS2 and WS2 nanosheets were prepared and characterized. Depending on the preparation procedures, trigonal prismatic (2H) or octahedral (1T) coordination of the metal atoms were obtained, exhibiting metallic (1T) or semiconducting (2H) character. Both MoS2 and WS2 nanosheets were found exhibiting large nonlinear optical (N...

Electrochemical reactions for hydrogen and hydrogen peroxide production are essential for energy conversion to diminish energy crisis, but still lack efficient electrocatalysts. Development of non\-noble metal bifunctional electrocatalysts for hydrogen evolution and 2e oxygen reduction reaction to ease reaction kinetics is a challenging task. Integ...

Nanoparticles (NPs) of conjugated polymers in intimate contact with sheets of graphene oxide (GO) constitute a promising class of water-dispersible nanohybrid materials of increased interest for the design of sustainable and improved optoelectronic thin-film devices, revealing properties exclusively pre-established upon their liquid-phase synthesis...

Through a nucleophilic substitution reaction made on C60Br24 a new cyanofullerene derivative has been synthesized. The thermogravimetric analysis (TGA) has led to the following stoichiometry for the new compound: [C60(CN)7]–[Bu4N]⁺ which was further confirmed both with the X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectrosc...

Morphological control at the nanoscale paves the way to fabricate nanostructures with desired plasmonic properties. In this study, we discuss the nanoengineering of plasmon resonances in 1D hollow nanostructures of two different AuAg nanotubes, including completely hollow nanotubes and hybrid nanotubes with solid Ag and hollow AuAg segments. Spatia...

Conventional epitaxy plays a crucial role in current state-of-the art semiconductor technology, as it provides a path for accurate control at the atomic scale of thin films and nanostructures, to be used as the building blocks in nanoelectronics, optoelectronics, sensors, etc. Four decades ago, the terms "van der Waals" (vdW) and "quasi-vdW (Q-vdW)...

Covalent functionalization of tungsten disulfide (WS2) with photo‐ and electro‐active nickel‐porphyrin (NiP) is reported. Exfoliated WS2 interfacing NiP moieties with 1,2‐dithiolane linkages is assayed in the oxygen evolution reaction under both dark and illuminated conditions. The hybrid material presented, WS2−NiP, is fully characterized with com...

Morphological control at the nanoscale paves the way to fabricate nanostructures with desired plasmonic properties. We report the nanoengineering of plasmon resonances in 1D hollow nanostructures of two different AuAg nanotubes; completely hollow nanotubes and hybrid nanotubes comprising solid Ag and hollow AuAg segments. Spatially resolved plasmon...

Photo-rechargeable (solar) battery can be considered as an energy harvesting cum storage system, where it can charge the conventional metal-ion battery using light instead of electricity, without having other parasitic reactions. Here we demonstrate a two-electrode lithium ion solar battery with multifaceted TiS2-TiO2 hybrid sheets as cathode. Choi...

The mechanical robustness of superhydrophobic surface is essential for practical applications. In this work, multi-walled carbon nanotubes with copious hydroxyl groups (MWCNTs-OH) were firstly silanized, with the presence of a small amount of HCl aquesous solution as catalyst, by trimethoxymethylsiane (MTMS) in petroleum ether. Upon hydrolyzation a...

Water electrolysis is a promising and environmentally friendly means for renewable energy storage. Recent progress in the development of anion exchange membrane (AEM) opened new perspectives for high-performance anode catalysts...

Easy and effective modification approaches for transition metal dichalcogenides are highly desired in order to make them active toward electrocatalysis. In this manner, we report functionalized molybdenum diselenide (MoSe2) and tungsten diselenide (WSe2) via metal-ligand coordination with pyridine rings for the subsequent covalent grafting of a cob...

Measuring electronic Raman scattering (ERS) has become an efficient method for structural characterization of metallic single-wall carbon nanotubes (SWCNT). However, applying this method to other types of SWCNT-based structures, e.g., those with strong van der Waals (VDW) coupling, is currently not well studied. In this work, we combine electron di...

All-graphenic carbon morphologies grown on individual carbon nanotubes (CNTs) consisting of short-fiber segments bearing sharp micro-/nano-cones at both ends were mounted as new probes for scanning probe microscopies (SPM). Three mounting procedures were tested, two based on focused ion and/or electron beam processes operated in scanning electron m...

The main goal of researchers is to obtain cheap cocatalysts that can promote the photocatalytic activity of catalysts. In this work, a series of CoS2/g-C3N4 (denoted as CoS2/CN) composite photocatalysts were synthesized by photodepositing CoS2 on g-C3N4 surface. The size of CoS2 species could be tuned from single-atom to nanometer scale, which had...

A frontier challenge in single‐atom (SA) catalysis is the design of fully inorganic sites capable of emulating the high reaction selectivity traditionally exclusive of organometallic counterparts in homogeneous catalysis. Modulating the direct coordination environment in SA sites, via the exploitation of the oxide support's surface chemistry, stand...

Explosive percolation is an experimentally-elusive phenomenon where network connectivity coincides with onset of an additional modification of the system; materials with correlated localisation of percolating particles and emergent conductive paths can realise sharp transitions and high conductivities characteristic of the explosively-grown network...

A frontier challenge in single‐atom (SA) catalysis is the design of fully inorganic sites capable to emulate the high reaction selectivity traditionally exclusive of organometallic counterparts in homogenous catalysis. Modulating the direct coordination environment in SA sites, via the exploitation of the oxide support’s surface chemistry, stands a...

Designing electrocatalysts for HER in alkaline conditions to overcome the sluggish kinetics associated with the additional water dissociation step is a recognized challenge in promoting the hydrogen economy. To this end, delicately tuning the atomic-scale structure and surface composition of nanoparticles is a common strategy and, specifically, mak...

While cobaloximes have been protagonists in the molecular (photo)catalytic hydrogen evolution reaction field, researchers originally shed light on the catalytically active metallic center. However, the specific chemical environment of cobalt, including equatorial and axial ligation, has also a strong impact on the catalytic reaction. In this articl...

Electrochemical reactions for hydrogen and hydrogen peroxide production are essential for energy conversion to diminish the energy crisis but still lack efficient electrocatalysts. Development of non-noble metal bifunctional electrocatalysts for the hydrogen evolution reaction and 2e- oxygen reduction reaction to ease reaction kinetics is a challen...

Achieving room-temperature valley polarization in two-dimensional (2D) atomic layers (2D materials) by substitutional doping opens new avenues of applications. Here, monolayer MoS2, when doped with vanadium at low (0.1 atomic %) concentrations, is shown to exhibit high spin-valley coupling, and hence a high degree of valley polarization at room-tem...

High aspect-ratio gold nanostructures sustain Fabry–Perot-like surface plasmon responses from infrared to visible light energies. We show that some resonances can be tuned by means of laser irradiation, where low energy modes stay unperturbed. After laser irradiation, gold nanowires’ tips are transformed into nanoparticles of various sizes joint to...

Photocatalytic production of H2 from the decomposition of water has attracted increased attention, as the environmental damages caused by the rapid evolution of industry are threatening the development of human society. This energy production is considered a green and eco-friendly resource. It has the potential to replace the carbon component of fu...

Ir/TiO2 catalysts promoted by niobium have been synthesized, characterized by different complementary techniques, and tested for the total oxidation of a set of alkanes and their mixtures. The addition of appropriate amounts of niobium to Ir/TiO2 catalysts resulted in a remarkable increase in the catalytic activity compared to the Nb-free Ir/TiO2 c...

Designing electrocatalysts for HER in alkaline conditions to overcome the sluggish kinetics associated with the additional water dissociation step is a recognized challenge in promoting the hydrogen economy. To this end, delicately tuning the atomic-scale structure and surface composition of nanoparticles is a common strategy and, specifically, mak...

Continuous miniaturization of electronics demands the development of interconnectors with high ampacity and high conductivity, which conventional conductors such as copper and gold cannot offer. Here we report the synthesis of Sr-deficient misfit SrxCoO2-CoO2 nanotubes by a novel crystal conversion method and investigate their electrical properties...

Graphene-based carbon micro-/nano-cones were prepared by depositing pyrolytic carbon onto individual carbon nanotubes as supports using a specific chemical vapor deposition process. They were investigated by means of high-resolution scanning electron microscopy, low-voltage aberration-corrected transmission electron microscopy, Raman spectroscopy,...

Nanotubes of transition metal dichalcogenides such as WS2 and MoS2 offer unique quasi-1D properties and numerous potential applications. Replacing sulfur by selenium would yield ternary WS2(1-x)Se2x (0 ≤ x ≤ 1; WSSe) nanotubes, which are expected to reveal strong modulation in their absorption edge as a function of selenium content, xSe. Solid WO2....

We explore the possibility of applying physical phase plates (PPs) in combination with aberration-corrected transmission electron microscopy. Phase-contrast transfer characteristics are calculated and compared for a thin-film based Zernike PP, a hole-free (HF) or Volta PP and an electrostatic Zach PP, considering their phase-shifting properties in...

Pyrolysis of formamidinium halide salts (FAI, FABr) results in a new type of amorphous carbon nitride materials with a mass fraction of 40–50% nitrogen content. Pyrolysis temperature drives final chemical composition, morphology, optical and electrical properties of the material independently of the halide precursor and identifying triazine ring, i...

There is a pressing need for reliable, reproducible and accurate measurements of graphene’s properties, through international standards, to facilitate industrial growth. However, trustworthy and verified standards require rigorous metrological studies, determining, quantifying and reducing the sources of measurement uncertainty. Towards this effort...

While graphene-based materials hold a strong potential as electrocatalysts, owing to their astonishing properties and functionalization capability, their intrinsic catalytic activity is more often masked under the umbrella of the precious and industrial metals that are used as counterparts for boosting the electrocatalytic performance. In the prese...

Double-walled carbon nanotubes (DWNTs), often regarded as the simplest one-dimensional (1D) van der Waals moiré superlattices, are the ideal structures to explore the interlayer coupling, including mechanical and electronical coupling, at the nanoscale in 1D systems. By combining spatial modulation spectroscopy (SMS) and resonant Raman scattering (...

Opto-spintronics is an emerging field where ultra-thin magnetic-semiconductors having high spin-valley coupling play an important role. Here, we demonstrate substitutional vanadium (V) doping in MoS$_2$ lattice in different extent, leading to the coexistence of photoluminescence (PL), valleypolarization (~32%), and valley splitting (~28 meV shift i...

Development of graphene/perovskite heterostructures mediated by polymeric materials may constitute a robust strategy to resolve the environmental instability of metal halide perovskites and provide barrierless charge transport. Herein, a straightforward approach for the growth of per-ovskite nano-crystals and their electronic communication with gra...

Photocatalytic production of H2 from the decomposition of water has attracted increased attention, as the environmental damages caused by the rapid evolution of industry are threatening the development of human society. This energy production is considered a green and eco-friendly resource. It has the potential to replace the carbon component of fu...

Lithium titanium oxide thin films are increasingly popular anode materials in microbatteries and hybrid supercapacitors, due to their improved safety, cost and cycle lifetime. So far, research efforts have mainly focused on the pure spinel phase Li4Ti5O12 (LTO) and only a small fraction is dedicated to a broader spectrum of titanium-based metal oxi...

Photothermal Therapy In article number 2106932, Manuel Arruebo, Victor Sebastian, and co‐workers demonstrate a facile and effective procedure to assemble near‐infrared‐sensitive Pd nanosheets into a drug‐loaded biopolymeric nanoparticle, resulting in an efficient theragnostic vector. This vector is capable of coupling the NIR plasmon resonance abso...

We explore the possibility of applying physical phase plates (PPs) in combination with aberration-corrected transmission electron microscopy. Phase-contrast transfer characteristics are calculated and compared for a thin-film based Zernike PP, a hole-free (HF) or Volta PP and an electrostatic Zach PP, considering their phase-shifting properties in...

Nanoparticles (NPs) which combine several magnetic phases offer wide perspectives for cutting edge applications because of the high modularity of their magnetic properties. Besides the addition of the magnetic characteristics intrinsic to each phase, the interface that results from core-shell and, further, from onion structures leads to synergistic...

The long-standing debate about the morphology of colloidal methylammonium lead bromide perovskites nanocrystals, manufactured by our nontemplate synthetic strategy reported in 2014, is now resolved; specifically, the highest green emissive...

The realization of novel heterostructures arising from the combination of nanomaterials is an effective way to modify their physicochemical and electrocatalytic properties, giving them enhanced characteristics stemming from their individual constituents. Interfacing carbon nanohorns (CNHs) possessing high porosity, large specific surface area and g...

Download link before December 15, 2021: https://authors.elsevier.com/a/1d~0a1zUAOOQG Single-walled carbon nanotubes possess the unique ability to tune their functional properties by modifying the outer surface or interior space. Using the same modifier – sulfur, we demonstrate a difference in sensing properties of coated and filled single-walled...

Development of synthetic strategies towards two-dimensional laminar transition metal dichalcogenide/graphene heterostructures is of particular interest for the electrocatalysis of the hydrogen evolution reaction (HER). Herein, we describe the preparation of...

The control of the magnetization inversion dynamics is one of the main challenges driving the design of new nanostructured magnetic materials for magnetoelectronic applications. Nanoparticles with onion-like architecture offer a...

Graphitic carbon nitride (g-C3N4) possessing high thermal and chemical stability, non-toxicity, facile synthesis, and low band gap energy is a promising candidate for photocatalytic applications. In this study, bulk and...

MoS2 has been explored as a potential material for hydrogen evolution reaction (HER) and lithium‐ion batteries (LIBs). However, the limited number of active sites and poor conductivity restrain its applications. Herein, a facile method is reported to construct MoS2 nanosheets (MoS2 NSs) grown on agar‐derived 3D nitrogen‐doped porous carbon (MoS2‐NP...

Covalent functionalization of chemically exfoliated molydbenum disulfide (ce-MoS2) with hydrophobic poly(methyl methacrylate) and hydrophilic poly(acrylic acid) polymers, in a single-step without additives, is presented. The nature of chemical modification and the impact on the structure of ce-MoS2 were spectroscopically investigated. Complexation...

Band gap engineering of atomically thin two-dimensional (2D) materials has attracted a huge amount of interest as a key aspect to the application of these materials in nanooptoelectronics and nanophotonics. Low-loss electron energy loss spectroscopy has been employed to perform a direct measurement of the band gap in atomically thin MoxW(1−x)S2 nan...

The incorporation of plasmonic nanoconstructs in biodegradable polymeric nanoparticles (NPs), together with therapeutic drugs in a controlled procedure is of interest for different applications in Nanomedicine. Advanced hybrid nanomaterials can be engineered by combining the in situ formation of plasmonic palladium nanosheets (NSs) and the proper i...

Laminated metal dichalcogenides are candidates for different potential applications ranging from catalysis to nanoelectronics. However, efforts are still needed to optimize synthesis methods aiming to control the number of layers, morphology, and crystallinity, parameters that govern the properties of the synthesized materials. Another important pa...

Ruddlesden‐Popper lead halide perovskite (RP‐LHP) nano‐nanostructures can be regarded as self‐assembled quantum wells or superlattices of 3D perovskites with an intrinsic quantum well thickness of a single or a few (n=2‐4) lead halide layers; the quantum wells are separated by organic layers. They can be scaled down to a single quantum well dimensi...

Boron/nitrogen, co-doped, carbon nano-onions (BN-CNOs) have recently shown great promise as catalysts for the oxygen reduction reaction, due to the improved electronic properties imparted by the dopant atoms; however, the interactions of BN-CNOs with biological systems have not yet been explored. In this study, we examined the toxicological profile...

Ruddlesden‐Popper lead halide perovskite (RP‐LHP) nano‐nanostructures can be regarded as self‐assembled quantum wells or superlattices of 3D perovskites with an intrinsic quantum well thickness of a single or a few ( n =2‐4) lead halide layers; the quantum wells are separated by organic layers. They can be scaled down to a single quantum well dimen...

The development of noble-metal free electrocatalysts is of high importance for clean energy conversion applications. MoS$_2$ has been considered as a promising low cost catalyst for the hydrogen evolution reaction (HER), however its activity is limited by poor conductivity and low abundance of active sites. Moreover, its suitability as an effective...

Significance Materials with the absence of inversion symmetry are fundamentally interesting. The synthesis of such asymmetric structures remains a critical challenge in material science. Despite the large interest in Janus nanotubes, no report of synthesized nanotubes with asymmetric structure has been published. Here, we demonstrate a successful s...

Zinc indium sulfide belongs to the family of layered ternary chalcogenides. Although ZnIn2S4 has a suitable bandgap in the visible range, its optoelectronic properties are not fully investigated. Most photodetectors based on layered semiconductors suffer from large dark currents, which hamper their performance and energy efficiency. In this work, h...

The realization of novel heterostructures arising from the combination of nanomaterials is an effective way to modify their physicochemical and electrocatalytic properties, giving them enhanced characteristics stemming from their individual constituents. Interfacing carbon nanohorns (CNHs) possessing high porosity, large specific surface area, and...

Numerous physical phase plates (PP) for phase-contrast enhancement in transmission electron microscopy (TEM) have been proposed and studied with the hole-free or Volta PP having a high impact and interest in recent years. This study is concerned with comparative TEM image simulations considering realistic descriptions of various PP approaches and s...

Numerous physical phase plates (PP) for phase-contrast enhancement in transmission electron microscopy (TEM) have been proposed and studied with the hole-free or Volta PP having a high impact and interest in recent years. This study is concerned with comparative TEM image simulations considering realistic descriptions of various PP approaches and s...