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Sandwich-like V 2 O 5 /graphene composites with adjustable graphene content (denoted as V 2 O 5 /xG) were designed to demonstrate the effects of electrode structure and wetting characteristics on zinc storage properties. The V 2 O 5 /5G with 10.4% graphene content exhibits effective inhibition of vanadium dissolution, high capacity and excellent cycling stability. [Display omitted] Improving the stability of the layered structure and suppressing vanadium dissolution during repeated Zn2+ insertion/extraction processes are considered to be the key to promote the electrochemical stability of vanadium-based cathodes for ZIBs. In this work, a group of sandwich-like V 2 O 5 /graphene composites (V 2 O 5 /xG) were controllably fabricated by tuning the amount of hydrophobic graphene. With the increase of graphene content, the corresponding electrochemical properties show a parabolic trend that increase first and then decrease. A maximum capacity of 270 mAh g−1 after 100 cycles at 0.1 A g−1 and a superior cycle stability with 82.4% capacitance retention after 6000 cycles at 10 A g−1 are achieved when the amount of graphene is about 10.4% (that is V 2 O 5 /5G). The addition of graphene has been proven not only to act as an effective conductive network to promote charge transfer and enhance the pseudocapacitance effect on the electrode surface; but also to increase the electrode hydrophobicity, effectively inhibiting the dissolution of vanadium, and promoting the desolvation and diffusion kinetics of hydrated zinc ions. Moreover, the graphene layer, as a structural stabilizer, effectively prevents the structure of the active component V 2 O 5 from collapsing during cycling, contributing to the long-term cycle life. [ABSTRACT FROM AUTHOR]

PbO 2 , PbO 2 /Pb 3 O 4 composite, and Pb 3 O 4 were synthesized respectively via the simple hydrothermal method under different reaction durations (3–48 ​h). All the prepared samples were used as anode materials to decontaminate methyl orange (MO) to explore the corresponding electrochemical advanced oxidation performance. The detailed experimental designs suggested that the combination of PbO 2 and Pb 3 O 4 offered enhanced electrochemical advanced oxidation performance, which was due to possible synergistic effects. XPS results suggest that the content of adsorbed oxygen species (O ads) is obviously higher in PbO 2 /Pb 3 O 4 composite. It is very likely due to more oxygen vacancies in the crystal structure of PbO 2 /Pb 3 O 4 composite, which will adsorb more oxygen species, promote charge transfer and provide more electrochemical active surface area to generate oxidizing agents. Besides, the presence of Pb 3 O 4 can suppress the oxygen evolution and improve the accelerated life. Meanwhile, the effects of current density, catalyst loading amount and initial MO concentration on electro-catalysis degradation of MO were explored. Experimental results suggested that MO removal efficiency was 94.3%, the reaction kinetic constant could reach 2.08 ⅹ 10-2 min-1, and COD removal efficiency was 34.2% after 150 ​min of reaction under optimized conditions: current density was 5 ​mA ​cm-2, catalyst loading amount was 1 ​mg ​cm-2 and initial MO concentration was 50 ​mg ​L-1. Furthermore, possible degradation mechanisms of MO was proposed according to the analyzed results obtained from UV–Vis and HPLC-MS. Relative ratio of PbO 2 and Pb 3 O 4 can be altered by changing the hydrothermal reactions durations, and PbO 2 /Pb 3 O 4 composite exhibited enhanced electrochemical advanced oxidation performance. [Display omitted] • Ratio of PbO 2 and Pb 3 O 4 can be adjusted by hydrothermal reaction durations. • PbO 2 /Pb 3 O 4 composite displayed enhanced electro-catalytic performance. • Role of different operating conditions was investigated. • Degradation byproducts of MO were identified and the possible pathways were proposed. [ABSTRACT FROM AUTHOR]