Xingli Zou

Electrodeposition behavior and characterization of copper-zinc alloy in deep eutectic solvent

AbstractCu–Zn alloy films have been electrodeposited directly from their oxide precursors in choline chloride (ChCl)/urea-based deep eutectic solvent (DES). The reaction mechanism and the influence of the cathodic potential on the characteristics of the Cu–Zn alloy films are studied. Cyclic voltammetry and energy dispersive spectroscopy analyses reveal that the reduction of Cu(II) species relatively more preferentially occurs in comparison with the reduction of Zn(II) species, and Cu–Zn codeposition process can be controlled in the DES. Chronoamperometric investigation further confirms that the electrodeposition of Cu–Zn alloy on a Fe electrode follows the three-dimensional instantaneous nucleation-growth process. The micro/nanostructured Cu–Zn alloy films with different phase compositions can be facilely produced by controlling the cathodic potential. The obtained Cu–Zn alloy films typically exhibit enhanced corrosion resistances in 3xa0wt% NaCl aqueous solution. It is suggested that Cu–Zn alloy films can be sustainably electrodeposited from their abundant and inexpensive oxide precursors in DES.Graphical AbstractMicro/nanostructured Cu−Zn alloy films have been electrodeposited directly from CuO and ZnO precursors in deep eutectic solvent (DES), the electrochemical reaction mechanism and the nucleation-growth process of Cu−Zn alloy in the DES are investigated.n

Facile electrosynthesis of silicon carbide nanowires from silica/carbon precursors in molten salt

Silicon carbide nanowires (SiC NWs) have attracted intensive attention in recent years due to their outstanding performances in many applications. A large-scale and facile production of SiC NWs is critical to its successful application. Here, we report a simple method for the production of SiC NWs from inexpensive and abundantly available silica/carbon (SiO2/C) precursors in molten calcium chloride. The solid-to-solid electroreduction and dissolution-electrodeposition mechanisms can easily lead to the formation of homogenous SiC NWs. This template/catalyst-free approach greatly simplifies the synthesis procedure compared to conventional methods. This general strategy opens a direct electrochemical route for the conversion of SiO2/C into SiC NWs, and may also have implications for the electrosynthesis of other micro/nanostructured metal carbides/composites from metal oxides/carbon precursors.

Electrosynthesis of Ti 5 Si 3 , Ti 5 Si 3 /TiC, and Ti 5 Si 3 /Ti 3 SiC 2 from Ti-Bearing Blast Furnace Slag in Molten CaCl 2

Ti5Si3, Ti5Si3/TiC, and Ti5Si3/Ti3SiC2 have been electrochemically synthesized from the Ti-bearing blast furnace slag/TiO2 and/or C mixture precursors at a cell voltage of 3.8 V and 1223xa0K to 1273xa0K (950xa0°C to 1000xa0°C) in molten CaCl2. The pressed porous mixture pellets were used as the cathode, and a solid oxide oxygen-ion-conducting membrane (SOM)-based anode was used as the anode. The phase composition and morphologies of the cathodic products were systematically characterized. The final products possess a porous nodular microstructure due to the interconnection of particles. The variations of impurity elements, i.e., Ca, Mg, and Al, have been analyzed, and the result shows that Ca and Mg can be almost completely removed; however, Al cannot be easily removed from the pellet due to the formation of Ti-Al alloys during the electroreduction process. The electroreduction process has also been investigated by the layer-depended phase composition analysis of the dipped/partially reduced pellets to understand the detailed reaction process. The results indicate that the electroreduction process of the Ti-bearing blast furnace slag/TiO2 and/or C mixture precursors can be typically divided into four periods, i.e., (i) the decomposition of initial Ca(Mg,Al)(Si,Al)2O6, (ii) the reduction of Ti/Si-containing intermediate phases, (iii) the removal of impurity elements, and (iv) the formation of Ti5Si3, TiC, and Ti3SiC2. It is suggested that the SOM-based anode process has great potential to be used for the direct and facile preparation of Ti alloys and composites from cheap Ti-containing ores.

Electrochemical Fabrication of Micro/Nanoporous Copper by Electrosynthesis-Dealloying of Cu–Zn Alloy in Deep Eutectic Solvent

The electrodeposition of Cu–Zn alloy films on a Ni substrate from CuO and ZnO precursors in choline chloride (ChCl)/urea (1:2 molar ratio) based deep eutectic solvent (DES) was firstly carried out. Then, micro/nanoporous Cu films were fabricated by further electro-dealloying of the synthesized Cu–Zn alloy films. XRD analysis indicates that the phase compositions of the deposited Cu–Zn alloys are Cu5Zn8 and CuZn5. Further investigation shows that the more-active component Zn would be dissolved during the electro-dealloying process, and porous Cu can be obtained. The result reveals that the electrosynthesis-dealloying process may provide a promising strategy for the production of micro/nanoporous Cu at low temperature.

Designed synthesis of SiC nanowire-derived carbon with dual-scale nanostructures for supercapacitor applications

The preparation of one-dimensional carbon materials with complex dual-scale nanostructures for supercapacitor applications still remains a challenge. Herein we report a simple strategy for electrosynthesis of silicon carbide nanowire (SiC NW)-derived carbon with dual-scale nanostructures for high performance supercapacitors. This method is highlighted by using solid oxide membrane technology to directly convert powdered silicon dioxide/carbon precursors into SiC NWs, and then the synthesized SiC NWs are further transformed into mesoporous silicon carbide-derived carbon nanowires (SiC-CDC NWs) via a subsequent in situ molten salt electrochemical etching process. Benefitting from their dual-scale nanostructures, these SiC-CDC NWs exhibit highly reversible specific capacitance of 260 F g−1 at 1 A g−1 and good cyclability (97.9% after 5000 cycles) in 6 M KOH aqueous solution without the need for doping the SiC-CDC NWs. It is suggested that this process is a promising general approach for synthesizing CDC materials with dual-scale nanostructures for energy storage applications.