Staff directory
Xiang Zhang
Fellowship Doctoral Student
China Scholarship Council (CSC),
Universidad Autónoma de Barcelona (UAB)
xiang.zhang(ELIMINAR)@icn2.cat
Supramolecular NanoChemistry and Materials
Publications
2021
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Control of spin-charge conversion in van der Waals heterostructures
Galceran R., Tian B., Li J., Bonell F., Jamet M., Vergnaud C., Marty A., García J.H., Sierra J.F., Costache M.V., Roche S., Valenzuela S.O., Manchon A., Zhang X., Schwingenschlögl U. APL Materials; 9 (10, 100901) 2021. 10.1063/5.0054865. IF: 5.096
The interconversion between spin and charge degrees of freedom offers incredible potential for spintronic devices, opening routes for spin injection, detection, and manipulation alternative to the use of ferromagnets. The understanding and control of such interconversion mechanisms, which rely on spin-orbit coupling, is therefore an exciting prospect. The emergence of van der Waals materials possessing large spin-orbit coupling (such as transition metal dichalcogenides or topological insulators) and/or recently discovered van der Waals layered ferromagnets further extends the possibility of spin-to-charge interconversion to ultrathin spintronic devices. Additionally, they offer abundant room for progress in discovering and analyzing novel spin-charge interconversion phenomena. Modifying the properties of van der Waals materials through proximity effects is an added degree of tunability also under exploration. This Perspective discusses the recent advances toward spin-to-charge interconversion in van der Waals materials. It highlights scientific developments which include techniques for large-scale growth, device physics, and theoretical aspects. © 2021 Author(s).
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Ferromagnetic metallic Sr-rich Ln1/2A1/2CoO3 cobaltites with spontaneous spin rotation
Padilla-Pantoja J., Romaguera A., Zhang X., Herrero-Martín J., Fauth F., Blasco J., García-Muñoz J.L. Physical Review B; 104 (5, 054411) 2021. 10.1103/PhysRevB.104.054411. IF: 4.036
The Pr0.50Sr0.50CoO3 perovskite exhibits unique magnetostructural properties among the rest of ferromagnetic (FM)/metallic Ln0.50Sr0.50CoO3 compounds. The sudden orthorhombic-tetragonal (Imma→I4/mcm) structural transition produces an unusual magnetic behavior vs temperature and external magnetic fields. The symmetry change is responsible for a spontaneous spin rotation in this metallic oxide. We have studied half-doped Ln0.50(Sr1-xAx)0.50CoO3 cobaltites varying the ionic radius rA of A-site cations (divalent cations and lanthanides) to complete the T-rA phase diagram. The influence of the structural distortion and the A-cation size for the occurrence of a spontaneous spin reorientation in the metallic state has been investigated. As the magnetization reorientation is driven by the temperature-induced collapse of the orthorhombic distortion, a careful investigation of the structural symmetry is presented, varying the structural distortion of the Sr-rich half-doped cobaltites by means of both compositional and temperature changes. The region in the phase diagram of these FM/metallic cobaltites where Fm′m′m magnetic symmetry replaces Im′m′a was determined. In that region, the magnetization direction has rotated 45 ° within the a-b plane from the former to the latter. © 2021 American Physical Society.
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Mesoporous silica coated CeO2nanozymes with combined lipid-lowering and antioxidant activity induce long-term improvement of the metabolic profile in obese Zucker rats
Parra-Robert M., Zeng M., Shu Y., Fernández-Varo G., Perramón M., Desai D., Chen J., Guo D., Zhang X., Morales-Ruiz M., Rosenholm J.M., Jiménez W., Puntes V., Casals E., Casals G. Nanoscale; 13 (18): 8452 - 8466. 2021. 10.1039/d1nr00790d. IF: 7.790
Obesity is one of the most important public health problems that is associated with an array of metabolic disorders linked to cardiovascular disease, stroke, type 2 diabetes, and cancer. A sustained therapeutic approach to stop the escalating prevalence of obesity and its associated metabolic comorbidities remains elusive. Herein, we developed a novel nanocomposite based on mesoporous silica coated cerium oxide (CeO2) nanozymes that reduce the circulating levels of fatty acids and remarkably improve the metabolic phenotype in a model of obese Zucker rats five weeks after its administration. Lipidomic and gene expression analyses showed an amelioration of the hyperlipidemia and of the hepatic and adipose metabolic dysregulations, which was associated with a down-regulation of the hepatic PI3K/mTOR/AKT pathway and a reduction of the M1 proinflammatory cytokine TNF-a. In addition, the coating of the CeO2 maximized its cell antioxidant protective effects and minimized non-hepatic biodistribution. The one-pot synthesis method for the nanocomposite fabrication is implemented entirely in aqueous solution, room temperature and open atmosphere conditions, favoring scalability and offering a safe and translatable lipid-lowering and antioxidant nanomedicine to treat metabolic comorbidities associated with obesity. This approach may be further applied to address other metabolic disorders related to hyperlipidemia, low-grade inflammation and oxidative stress. © 2021 The Royal Society of Chemistry.
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Quasi-double-star nickel and iron active sites for high-efficiency carbon dioxide electroreduction
Zhang T., Han X., Liu H., Biset-Peiró M., Zhang X., Tan P., Tang P., Yang B., Zheng L., Morante J.R., Arbiol J. Energy and Environmental Science; 14 (9): 4847 - 4857. 2021. 10.1039/d1ee01592c. IF: 38.532
Although the Faraday efficiencies (FEs) obtained on most of the Ni based single-atom catalysts (Ni-N-C) are satisfactory (generally >90%) for the electrochemical transfer CO2 to CO, their practical application is still limited by their high overpotentials (>600 mV vs. RHE), which implies a higher energy consumption to drive the CO2 RR. In this work, we have prepared a quasi-double star catalyst composed of nearby Ni and Fe active sites via a simple pyrolysis of Ni and Fe co-doped Zn-based MOFs in order to achieve a high selectivity at a low overpotential during the CO2 RR. Specifically, the optimized Ni/Fe-N-C catalyst shows an exclusive selectivity (a maximum FE(CO) of 98%) at a low overpotential of 390 mV vs. RHE, which is superior to both the single metal counterparts (Ni-N-C and Fe-N-C catalysts) and other state-of-the-art M-N-C catalysts. The DFT results further reveal that regulating the catalytic CO2 RR performance via nearby Ni and Fe active sites can potentially break the activity benchmark of the single metal counterparts because the neighboring Ni and Fe active sites not only function in synergy to decrease the reaction barrier for the formation of COOH∗ and desorption of CO∗ in comparison to their single metal counterparts, but also prevent the undesired hydrogen evolution reaction (HER). This work presents a quasi-double-star catalyst composed of two metal sites for high-efficiency CO2 reduction, which paves the way for the rational design of bimetallic catalysts with separated active sites for other reactions. © The Royal Society of Chemistry.
2018
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Ultrasensitive binder-free glucose sensors based on the pyrolysis of in situ grown Cu MOF
Zhang X., Luo J., Tang P., Morante J.R., Arbiol J., Xu C., Li Q., Fransaer J. Sensors and Actuators, B: Chemical; 254: 272 - 281. 2018. 10.1016/j.snb.2017.07.024. IF: 5.667
A non-enzymatic glucose sensor based on carbon/Cu composite materials was developed by the in-situ growth and subsequent pyrolysis of metal-organic frameworks (MOFs) on Cu foam. After pyrolysis, SEM, HRTEM and STEM-EELS were employed to clarify the hierarchical Cu@porous carbon electrode. It is found that the Cu nanoparticles are uniformly embedded in the carbon matrix, carbon matrix in close contact with the pyrolized carbon sheets. The electrocatalytic activity of the Cu@porous carbon matrix electrode for glucose sensing was explored by cyclic voltammetry (CV) and chronoamperometry. The resulting Cu@porous carbon matrix electrode displays ultrahigh sensitivity (10.1 mA cm−2 mM−1), low detection limit (0.6 μM), short response time (less than 2 s) and good stability, indicating that the developed electrode is a promising glucose sensor. © 2017 Elsevier B.V.
2017
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A universal strategy for metal oxide anchored and binder-free carbon matrix electrode: A supercapacitor case with superior rate performance and high mass loading
Zhang X., Luo J., Tang P., Ye X., Peng X., Tang H., Sun S.-G., Fransaer J. Nano Energy; 31: 311 - 321. 2017. 10.1016/j.nanoen.2016.11.024. IF: 12.343
Despite the significant advances in preparing carbon-metal oxide composite electrodes, strategies for seamless interconnecting of these two materials without using binders are still scarce. Herein we design a novel method for in situ synthesis of porous 2D-layered carbon–metal oxide composite electrode. Firstly, 2D-layered Ni-Co mixed metal-organic frameworks (MOFs) are deposited directly on nickel foam by anodic electrodeposition. Subsequent pyrolysis and activation procedure lead to the formation of carbon–metal oxides composite electrodes. Even with an ultrahigh mass loading of 13.4 mg cm−2, the as-prepared electrodes exhibit a superior rate performance of 93% (from 1 to 20 mA cm−2), high capacitance (2098 mF cm−2 at a current density of 1 mA cm−2), low resistance and excellent cycling stability, making them promising candidates for practical supercapacitor application. As a proof of concept, several MOF derived electrodes with different metal sources have also been prepared successfully via the same route, demonstrating the versatility of the proposed method for the preparation of binder-free carbon–metal oxide composite electrodes for electrochemical devices. © 2016 Elsevier Ltd
2016
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Synergistic effects in 3D honeycomb-like hematite nanoflakes/branched polypyrrole nanoleaves heterostructures as high-performance negative electrodes for asymmetric supercapacitors
Tang P.-Y., Han L.-J., Genç A., He Y.-M., Zhang X., Zhang L., Galán-Mascarós J.R., Morante J.R., Arbiol J. Nano Energy; 22: 189 - 201. 2016. 10.1016/j.nanoen.2016.02.019. IF: 11.553
Rational assembly of unique branched heterostructures is one of the facile techniques to improve the electrochemical figure of merit of materials. By taking advantages of hydrogen bubbles dynamic template, hydrothermal method and electrochemical polymerization, branched polypyrrole (PPy) nanoleaves decorated honeycomb-like hematite nanoflakes (core-branch Fe2O3@PPy) are fabricated. X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, and scanning transmission electron microscopy in high angle annular dark field mode with electron energy loss spectroscopy were combined to elucidate the mechanisms underlying formation and morphogenesis evolution of core-branch Fe2O3@PPy heterostructures. Benefiting from the stability of honeycomb-like hematite nanoflakes and the high conductivity of PPy nanoleaves, the resultant core-branch Fe2O3@PPy exhibits an ultrahigh capacitance of 1167.8 F g-1 at 1 A g-1 in 0.5 M Na2SO4 aqueous solution. Moreover, the assembled bi-metal oxides asymmetric supercapacitor (Fe2O3@PPy//MnO2) gives rise to a maximum energy density of 42.4 W h kg-1 and a maximum power density of 19.14 kW kg-1 with an excellent cycling performance of 97.1% retention after 3000 cycles at 3 A g-1. These performance features are superior than previous reported iron oxide/hydroxides based supercapacitors, offering an important guideline for future design of advanced next-generation supercapacitors. © 2016 Elsevier Ltd.