Novel Ag@Nitrogen-doped Porous Carbon Composite with High Electrochemical Performance as Anode Materials for Lithium-ion Batteries

A novel Ag@nitrogen-doped porous carbon(Ag-NPC) composite was synthesized via a facile hydrothermal method and applied as an anode material in lithium-ion batteries(LIBs). Using this method, Ag nanoparticles(Ag NPs) were embedded in NPC through thermal decomposition of Ag NO_3 in the pores of NPC. The reversible capacity of Ag-NPC remained at 852 m Ah g^(-1)after 200 cycles at a current density of 0.1 A g^(-1), showing its remarkable cycling stability. The enhancement of the electrochemical properties such as cycling performance,reversible capacity and rate performance of Ag-NPC compared to the NPC contributed to the synergistic effects between Ag NPs and NPC.

CoNiP/NC polyhedrons derived from cobalt-based zeolitic imidazolate frameworks as an active electrocatalyst for oxygen evolution

The oxygen evolution reaction(OER)plays an important role in the development of energy conversation and storage technologies including water splitting and metal-air batteries,where the development of electrocatalysts is paramount.In this study,cobalt-nickel phosphide/N-doped porous carbon polyhedron electrocatalysts(CoNiP/NC)were prepared by a facile two-step carbonization method and subsequent phosphorization calcination in an Ar atmosphere using cobalt-based zeolitic imidazolate frameworks(ZIFs)as precursors.Among the electrocatalysts obtained by controlling the carbonization and phosphorization temperature,the CoNiP/NC700 catalyst,where 700 refers to the calcination temperature(°C),exhibited superior electrocatalytic activity for the OER with an onset overpotential of approximate 220 mV and an overpotential of approximate 300 mV in alkaline solution at a current density of 10 mA/cm2.The CoNi/NC and Co/NC Samples were also tested for comparison and CoNiP/NC exhibited the better electrocatalytic activity at all the temperatures tested.The superior electrocatalytic activity of the phosphorization hybrid material can be attributed to the superior synergistic effect of Co,Ni,P and C due to their strong electron coupling interactions.The interconnected amorphous carbon anchored the active Co compounds to avoid aggregation and maintained conducting channels for electron transfer.The composite electrocatalyst prepared herein is a promising candidate for use in electrocatalytic OERs.

Novel Co_3O_4 Nanoparticles/Nitrogen-Doped Carbon Composites with Extraordinary Catalytic Activity for Oxygen Evolution Reaction(OER)

Herein, Co_3O_4 nanoparticles/nitrogen-doped carbon(Co_3O_4/NPC) composites with different structures were prepared via a facile method. Structure control was achieved by the rational morphology design of ZIF-67 precursors, which were then pyrolyzed in air to obtain Co_3O_4/NPC composites. When applied as catalysts for the oxygen evolution reaction(OER), the M-Co_3O_4/NPC composites derived from the flower-like ZIF-67 showedsuperior catalytic activities than those derived from the rhombic dodecahedron and hollow spherical ZIF-67. The former M-Co_3O_4/NPC composite displayed a small overpotential of 0.3 V, low onset potential of 1.41 V, small Tafel slope of 83 m V dec^(-1), and a desirable stability.(94.7% OER activity was retained after 10 h.) The excellent performance of the flower-like M-Co_3O_4/NPC composite in the OER was attributed to its favorable structure.

Research on Tomato Bacterial Pith Necrosis

The pathogen and characteristics, infection cycle, occurrence regularity and damage symptoms of tomato bacterial pith necrosis are introduced in the paper. To control the disease, based on cultivation of resistant varieties, we should adopt the comprehensive prevention method of strengthening cultivation manage- ment, improving plant resistance, eradicating bacterial source and conducting chemical protection. The paper provides certain basis for reducing the damage of tomato bacterial pith necrosis, and improving yield and quality of tomato.