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Yang H.,Kunming University of Science and Technology | Chen B.,Kunming University of Science and Technology | Liu H.,Kunming University of Science and Technology | Guo Z.,Kunming University of Science and Technology | And 5 more authors.
International Journal of Hydrogen Energy | Year: 2014

An Al/conductive coating/α-PbO2-CeO2-TiO 2/β-PbO2-MnO2-WC-ZrO2 composite electrode material was prepared through electrochemical oxidation co-deposition on an Al/conductive coating/α-PbO2-CeO2-TiO 2 substrate. The effects of manganese nitrate concentration on the chemical composition, electrocatalytic activity, and stability of the composite anode material were investigated using energy dispersive X-ray spectroscopy, anode polarization curves, quasi-stationary polarization curves, electrochemical impedance spectroscopy, scanning electron microscopy, and X-ray diffraction. Results revealed that the WC and nano-ZrO2 content in the β-PbO2-MnO2-WC-ZrO2 composite coatings increased with increasing manganese nitrate concentration. Moreover, the highest values of 6.61 wt% and 3.51 wt%, respectively, were achieved at 80 g L -1 manganese nitrate. PbO2 content decreased and MnO 2 content increased with the increasing manganese nitrate concentration; both the descending and ascending trends were nonlinear. The Al/conductive coating/α-PbO2-CeO2-TiO 2/β-PbO2-MnO2-WC-ZrO2 composite electrode obtained at 80 g L-1 manganese nitrate concentration in plating solution exhibited reduced overpotential for oxygen evolution (0.610 V at 500 A m-2), highest electrocatalytic activity, longest service life (360 h at 40 C in 150 g L-1 H2SO4 solution at 2 A cm-2), and lowest cell voltage (2.75 V at 500 A m -2). Furthermore, the composite coating obtained with 80 g L -1 manganese nitrate had uniform crystal grains. The deposit formed was flat, dense, and crackless. © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserver. Source


Yang H.-T.,Kunming University of Science and Technology | Liu H.-R.,Kunming University of Science and Technology | Zhang Y.-C.,Kunming University of Science and Technology | Chen B.-M.,Kunming University of Science and Technology | And 4 more authors.
Advanced Materials Research | Year: 2013

In this paper, electrochemical behaviour of Pb-0.8%Ag anode during the 15 days galvanostatic electrolysis in acid zinc sulphate electrolyte solution was investigated with Cyclic Voltammetry (CV) techniques. The phase composition of the anodic oxide layers during the electrolysis was observed using X-Ray Diffraction (XRD). The results revealed that the electrochemical oxidation processes and phase formation varied obviously during the electrolysis for it is a process indicating the formation and stabilization of anodic oxide layer. With the increasing electrolysis time, the anodic peak(Pb→PbSO4) is mainly present a rise trend and gradually moved in the positive direction while the anodic peak(PbSO4→β-PbO2, PbO→α-PbO2) strongly moved in the negative direction. The cathodic peak(β-PbO2 and α-PbO2→PbSO4) and (PbO and PbSO4→Pb) mainly present a rise trend and gradually moved in the negative direction. Besides, the corrosion phase of the anodic oxide layers mainly consist of PbSO4, PbO, α-PbO2 and β-PbO2. With the increasing electrolysis time, the content of α-PbO2 presents a declining trend while the content of β-PbO2 a rising trend. The preferred growth orientation of α-PbO2 and β-PbO2 is (111) and (101) planes respectively. © (2013) Trans Tech Publications, Switzerland. Source


Yang H.-T.,Kunming University of Science and Technology | Liu H.-R.,Kunming University of Science and Technology | Zhang Y.-C.,Kunming University of Science and Technology | Chen B.-M.,Kunming University of Science and Technology | And 4 more authors.
International Journal of Minerals, Metallurgy and Materials | Year: 2013

An Al/Pb-0.3%Ag alloy composite anode was produced via composite casting. Its electrocatalytic activity for the oxygen evolution reaction and corrosion resistance was evaluated by anodic polarization curves and accelerated corrosion test, respectively. The microscopic morphologies of the anode section and anodic oxidation layer during accelerated corrosion test were obtained by scanning electron microscopy. It is found that the composite anode (hard anodizing) displays a more compact interfacial combination and a better adhesive strength than plating tin. Compared with industrial Pb-0.3%Ag anodes, the oxygen evolution overpotentials of Al/Pb-0.3%Ag alloy (hard anodizing) and Al/Pb-0.3%Ag alloy (plating tin) at 500 A·m-2 were lower by 57 and 14 mV, respectively. Furthermore, the corrosion rates of Pb-0.3%Ag alloy, Al/Pb-0.3%Ag alloy (hard anodizing), and Al/Pb-0.3%Ag alloy (plating tin) were 13.977, 9.487, and 11.824 g·m-2·h-1, respectively, in accelerated corrosion test for 8 h at 2000 A·m -2. The anodic oxidation layer of Al/Pb-0.3%Ag alloy (hard anodizing) is more compact than Pb-0.3%Ag alloy and Al/Pb-0.3%Ag alloy (plating tin) after the test. © 2013 University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg. Source


Qu W.,Kunming University of Science and Technology | Qu W.,State Key Laboratory Breeding Base of Complex Nonferrous Metal Resources Cleaning Utilization | Qu W.,Key Laboratory of Unconventional Metallurgy Education Ministry | Jin W.,State Key Laboratory Breeding Base of Complex Nonferrous Metal Resources Cleaning Utilization | And 5 more authors.
Advanced Materials Research | Year: 2012

Zinc acetate and Zn-oxo complex of Zn 4O(CH 3COO) 6 containing in the spent catalyst of vinyl synthesis were investigated by means of the first principles of density functional (DFT) methods. The geometries, energies, charge populations and local electron density distributions of the two compounds and their formate analogues were analyzed. Based on the pyrolysis characteristics of the spent catalyst, the thermodynamic properties of ΔG, ΔH and ΔS for possible decomposition reactions of zinc acetate and Zn 4O(CH 3COO) 6 were calculated as functions of temperature. The results provide a theoretical evidence that Zn 4O(CH 3COO) 6 is more stable than zinc acetate due to the regular Zn 4O and ZnO 4 tetrahedral coordination between Zn atoms and two kinds of O atoms. The preparation of Zn 4O(CH 3COO) 6 via the hydrolysis of zinc acetate is thermodynamically feasible. Zn 4O(CH 3COO) 6 is further decomposed into ZnO via a decarboxylation reaction rather than a hydrolysis reaction. © (2012) Trans Tech Publications, Switzerland. Source


Zhang M.,Kunming University of Science and Technology | Zhang M.,State Key Laboratory Breeding Base of Complex Nonferrous Metal Resources Cleaning Utilization | Wang H.,Kunming University of Science and Technology | Wang H.,State Key Laboratory Breeding Base of Complex Nonferrous Metal Resources Cleaning Utilization | And 2 more authors.
Advanced Materials Research | Year: 2012

A series of CuO-ZnO-CeO 2-ZrO 2/HZSM-5 catalysts were prepared and characterized by XRD, H 2-TPR. CO 2 hydrogenation to DME was carried out in a fixed bed reactor to test the catalytic performance of Ce-modified CuO-ZnO-ZrO 2/HZSM-5 catalyst under the condition of GHSV=1800 h -1, p=3.0 MPa and T=250 °C. The results indicate that the added CeO 2 improved the performance of the bifunctional catalysts, the CO 2 conversion and DME selectivity were obviously improved. CuO-ZnO-CeO 2-ZrO 2/HZSM-5 catalyst with Ce to Zr molar ratio of 1/1 showed the highest activity for DME synthesis from CO 2 hydrogenation. © (2012) Trans Tech Publications, Switzerland. Source

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