Staff directory Yue Zhang

Yue Zhang

Fellowship Doctoral Student
China Scholarship Council
Universitat Autònoma de Barcelona (UAB)
yue.zhang(ELIMINAR)@icn2.cat
Magnetic Nanostructures

Publications

2019

  • Ge-Doped ZnSb/β-Zn4Sb3 Nanocomposites with High Thermoelectric Performance

    Ostovari Moghaddam A., Shokuhfar A., Zhang Y., Zhang T., Cadavid D., Arbiol J., Cabot A. Advanced Materials Interfaces; (1900467) 2019. 10.1002/admi.201900467. IF: 4.713

    ZnSb/β-Zn4Sb3 nanocomposites are produced from Zn1.1−xGexSb mixtures using a two-step process. First, proper amounts of the three elements are mixed, melted, and reacted at 800 K. During this process, the nonstoichiometric mixture is crystallized in a combination of ZnSb and β-Zn4Sb3 phases. Then, the material is ball milled and subsequently hot pressed. Through this process, a dense ZnSb/β-Zn4Sb3 composite, consisting of β-Zn4Sb3 nanoinclusions embedded within a ZnSb matrix, is formed. The particular phase distribution of the final ZnSb/β-Zn4Sb3 composites is a consequence of the harder and more brittle nature of ZnSb than Zn4Sb3, which translates into a stronger reduction of the size of the ZnSb crystal domains during ball milling. This small particle size and the high temperature generated during ball milling result in the melting of the ZnSb phase and the posterior crystallization of the two phases in a ZnSb/β-Zn4Sb3 matrix/nanoinclusion-type phase distribution. This particular phase distribution and the presence of Ge result in excellent thermoelectric performances, with power factors up to 1.5 mW m−1 K−2, lattice thermal conductivities down to 0.74 W m−1 K−1, and a thermoelectric figures of merit, ZT, up to 1.2 at 650 K, which is among the highest ZT values reported for ZnSb. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


  • 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.


  • Porous NiTiO3/TiO2 nanostructures for photocatatalytic hydrogen evolution

    Xing C., Liu Y., Zhang Y., Liu J., Zhang T., Tang P., Arbiol J., Soler L., Sivula K., Guijarro N., Wang X., Li J., Du R., Zuo Y., Cabot A., Llorca J. Journal of Materials Chemistry A; 7 (28): 17053 - 17059. 2019. 10.1039/c9ta04763h. IF: 10.733

    We present a strategy to produce porous NiTiO3/TiO2 nanostructures with excellent photocatalytic activity toward hydrogen generation. In a first step, nickel-doped TiO2 needle bundles were synthesized by a hydrothermal procedure. Through the sintering in air of these nanostructures, porous NiTiO3/TiO2 heterostructured rods were obtained. Alternatively, the annealing in argon of the nickel-doped TiO2 needle bundles resulted in NiOx/TiO2 elongated nanostructures. Porous NiTiO3/TiO2 structures were tested for hydrogen evolution in the presence of ethanol. Such porous heterostructures exhibited superior photocatalytic activity toward hydrogen generation, with hydrogen production rates up to 11.5 mmol h-1 g-1 at room temperature. This excellent performance is related here to the optoelectronic properties and geometric parameters of the material. © 2019 The Royal Society of Chemistry.


2018

  • Crystallographically Textured Nanomaterials Produced from the Liquid Phase Sintering of BixSb2-xTe3 Nanocrystal Building Blocks

    Liu Y., Zhang Y., Ortega S., Ibáñez M., Lim K.H., Grau-Carbonell A., Martí-Sánchez S., Ng K.M., Arbiol J., Kovalenko M.V., Cadavid D., Cabot A. Nano Letters; 18 (4): 2557 - 2563. 2018. 10.1021/acs.nanolett.8b00263. IF: 12.080

    Bottom-up approaches for producing bulk nanomaterials have traditionally lacked control over the crystallographic alignment of nanograins. This limitation has prevented nanocrystal-based nanomaterials from achieving optimized performances in numerous applications. Here we demonstrate the production of nanostructured BixSb2-xTe3 alloys with controlled stoichiometry and crystallographic texture through proper selection of the starting building blocks and the adjustment of the nanocrystal-to-nanomaterial consolidation process. In particular, we hot pressed disk-shaped BixSb2-xTe3 nanocrystals and tellurium nanowires using multiple pressure and release steps at a temperature above the tellurium melting point. We explain the formation of the textured nanomaterials though a solution-reprecipitation mechanism under a uniaxial pressure. Additionally, we further demonstrate these alloys to reach unprecedented thermoelectric figures of merit, up to ZT = 1.96 at 420 K, with an average value of ZTave = 1.77 for the record material in the temperature range 320-500 K, thus potentially allowing up to 60% higher energy conversion efficiencies than commercial materials. © 2018 American Chemical Society.


  • High Thermoelectric Performance in Crystallographically Textured n-Type Bi2Te3- xSex Produced from Asymmetric Colloidal Nanocrystals

    Liu Y., Zhang Y., Lim K.H., Ibáñez M., Ortega S., Li M., David J., Martí-Sánchez S., Ng K.M., Arbiol J., Kovalenko M.V., Cadavid D., Cabot A. ACS Nano; 12 (7): 7174 - 7184. 2018. 10.1021/acsnano.8b03099. IF: 13.709

    In the present work, we demonstrate crystallographically textured n-type Bi2Te3-xSex nanomaterials with exceptional thermoelectric figures of merit produced by consolidating disk-shaped Bi2Te3-xSex colloidal nanocrystals (NCs). Crystallographic texture was achieved by hot pressing the asymmetric NCs in the presence of an excess of tellurium. During the hot press, tellurium acted both as lubricant to facilitate the rotation of NCs lying close to normal to the pressure axis and as solvent to dissolve the NCs approximately aligned with the pressing direction, which afterward recrystallize with a preferential orientation. NC-based Bi2Te3-xSex nanomaterials showed very high electrical conductivities associated with large charge carrier concentrations, n. We hypothesize that such large n resulted from the presence of an excess of tellurium during processing, which introduced a high density of donor TeBi antisites. Additionally, the presence in between grains of traces of elemental Te, a narrow band gap semiconductor with a work function well below Bi2Te3-xSex, might further contribute to increase n through spillover of electrons, while at the same time blocking phonon propagation and hole transport through the nanomaterial. NC-based Bi2Te3-xSex nanomaterials were characterized by very low thermal conductivities in the pressing direction, which resulted in ZT values up to 1.31 at 438 K in this direction. This corresponds to a ca. 40% ZT enhancement from commercial ingots. Additionally, high ZT values were extended over wider temperature ranges due to reduced bipolar contribution to the Seebeck coefficient and the thermal conductivity. Average ZT values up to 1.15 over a wide temperature range, 320 to 500 K, were measured, which corresponds to a ca. 50% increase over commercial materials in the same temperature range. Contrary to most previous works, highest ZT values were obtained in the pressing direction, corresponding to the c crystallographic axis, due to the predominance of the thermal conductivity reduction over the electrical conductivity difference when comparing the two crystal directions. © 2018 American Chemical Society.


  • Tin Diselenide Molecular Precursor for Solution-Processable Thermoelectric Materials

    Zhang Y., Liu Y., Lim K.H., Xing C., Li M., Zhang T., Tang P., Arbiol J., Llorca J., Ng K.M., Ibáñez M., Guardia P., Prato M., Cadavid D., Cabot A. Angewandte Chemie - International Edition; 2018. 10.1002/anie.201809847. IF: 12.102

    In the present work, we detail a fast and simple solution-based method to synthesize hexagonal SnSe2 nanoplates (NPLs) and their use to produce crystallographically textured SnSe2 nanomaterials. We also demonstrate that the same strategy can be used to produce orthorhombic SnSe nanostructures and nanomaterials. NPLs are grown through a screw dislocation-driven mechanism. This mechanism typically results in pyramidal structures, but we demonstrate here that the growth from multiple dislocations results in flower-like structures. Crystallographically textured SnSe2 bulk nanomaterials obtained from the hot pressing of these SnSe2 structures display highly anisotropic charge and heat transport properties and thermoelectric (TE) figures of merit limited by relatively low electrical conductivities. To improve this parameter, SnSe2 NPLs are blended here with metal nanoparticles. The electrical conductivities of the blends are significantly improved with respect to bare SnSe2 NPLs, what translates into a three-fold increase of the TE Figure of merit, reaching unprecedented ZT values up to 0.65. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim


2015

  • Cu2ZnSnS4-Ag2S Nanoscale p-n Heterostructures as Sensitizers for Photoelectrochemical Water Splitting

    Yu X., Liu J., Genç A., Ibáñez M., Luo Z., Shavel A., Arbiol J., Zhang G., Zhang Y., Cabot A. Langmuir; 31 (38): 10555 - 10561. 2015. 10.1021/acs.langmuir.5b02490. IF: 4.457

    A cation exchange-based route was used to produce Cu2ZnSnS4 (CZTS)-Ag2S nanoparticles with controlled composition. We report a detailed study of the formation of such CZTS-Ag2S nanoheterostructures and of their photocatalytic properties. When compared to pure CZTS, the use of nanoscale p-n heterostructures as light absorbers for photocatalytic water splitting provides superior photocurrents. We associate this experimental fact to a higher separation efficiency of the photogenerated electron-hole pairs. We believe this and other type-II nanoheterostructures will open the door to the use of CZTS, with excellent light absorption properties and made of abundant and environmental friendly elements, to the field of photocatalysis. © 2015 American Chemical Society.


  • Cu2ZnSnS4-PtM (M = Co, Ni) Nanoheterostructures for Photocatalytic Hydrogen Evolution

    Yu X., An X., Genç A., Ibáñez M., Arbiol J., Zhang Y., Cabot A. Journal of Physical Chemistry C; 119 (38): 21882 - 21888. 2015. 10.1021/acs.jpcc.5b06199. IF: 4.772

    We report the synthesis and photocatalytic and magnetic characterization of colloidal nanoheterostructures formed by combining a Pt-based magnetic metal alloy (PtCo, PtNi) with Cu2ZnSnS4 (CZTS). While CZTS is one of the main candidate materials for solar energy conversion, the introduction of a Pt-based alloy on its surface strongly influences its chemical and electronic properties, ultimately determining its functionality. In this regard, up to a 15-fold increase of the photocatalytic hydrogen evolution activity was obtained with CZTS-PtCo when compared with CZTS. Furthermore, two times higher hydrogen evolution rates were obtained for CZTS-PtCo when compared with CZTS-Pt, in spite of the lower precious metal loading of the former. Besides, the magnetic properties of the PtCo nanoparticles attached to the CZTS nanocrystals were retained in the heterostructures, which could facilitate catalyst purification and recovery for its posterior recycling and/or reutilization. © 2015 American Chemical Society.