脱合金制备纳米多孔Co及其超级电容器和对偶氮染料的降解性能

在0.5%(质量分数,下同)NH4F和1 mol/L (NH4)2SO4混合溶液中进行电化学脱合金Zr56Al16Co28非晶合金,制备出纳米多孔Co。这种纳米多孔Co具有良好的超级电容器性能,其比电容在2 A/g的电流密度下能达318 F/g;同时,纳米多孔Co在方波电位下对直接蓝6和酸性橙II等偶氮染料具有优异的降解能力,降解效率均高于96%,其单位质量纳米多孔Co电极材料的降解能力是等质量Zr56Al16Co28非晶合金的3.5倍。

A binder-free, flexible cathode for rechargeable Na-O_2 batteries

Rechargeable Na-O2 batteries have attracted significant attention as energy storage devices owing to their theoretically high energy storage capacity and the natural abundance of sodium. However, practical applications of this type of battery still suffer from low specific capability, poor cycle sta- bility, instable electrolytes, and unstable polymer binders. Herein, we report a facile method of synthesizing binder free and flexible cathodes with C0304 nanowire arrays vertically grown onto carbon textiles. When employed as a cathode for Na-O2 batteries, this cathode exhibits superior performance, including a reduction of charge overpotential, high specific capacity （4687 mAh/g）, and cycle stability up to 62 cycles. These enhanced performance can be attributed to the synergistic effect of the porosity and catalytic activity of the C0304 nanowire catalyst.

Iron-induced 3D nanoporous iron-cobalt oxyhydroxide on carbon cloth as a highly efficient electrode for oxygen evolution reaction

The development of highly efficient and cost-effective electrode materials for catalyzing the oxygen evolution reaction(OER)is crucial for water splitting technology.The increase in the number of active sites by tuning the morphology and structure and the enhancement of the reactivity of active sites by the incorporation of other components are the two main strategies for the enhancement of their catalytic performance.In this study,by combining these two strategies,a unique three-dimensional nanoporous Fe-Co oxyhydroxide layer coated on the carbon cloth(3D-FeCoOOH/CC)was successfully synthesized by in situ electro-oxidation methods,and directly used as a working electrode.The electrode,3D-FeCoOOH/CC,was obtained by the Fe doping process in(NH4)2Fe(SO4)2,followed by continuous in situ electro-oxidization in alkaline medium of“micro go chess piece”arrays on the carbon cloth(MCPAs/CC).Micro characterizations illustrated that the go pieces of MCPAs/CC were completely converted into a thin conformal coating on the carbon cloth fibers.The electrochemical test results showed that the as-synthesized 3D-FeCoOOH/CC exhibited enhanced activity for OER with a low overpotential of 259 mV,at a current density of 10 mA cm^–2,and a small Tafel slope of 34.9 mV dec^–1,as well as superior stability in 1.0 mol L^–1 KOH solution.The extensive analysis revealed that the improved electrochemical surface area,conductivity,Fe-Co bimetallic composition,and the unique 3D porous structure together contributed to the enhanced OER activity of 3D-FeCoOOH/CC.Furthermore,the synthetic strategy applied in this study could be extended to fabricate a series of Co-based electrode materials with the dopant of other transition elements.

Hierarchical Co3O4 porous nanowires as an efficient bifunctional cathode catalyst for long life Li-O2 batteries

Hierarchical Co3O4 porous nanowires （NWs） have been synthesized using a hydrothermal method followed by calcination. When employed as a cathode catalyst in non-aqueous Li-oxygen batteries, the Co3O4 NWs effectively improve both the round-trip efficiency and cycling stability, which can be attributed to the high catalytic activities of Co3O4 NWs for the oxygen reduction reaction and the oxygen evolution reaction during discharge and charge processes, respectively.

N,P-dual doped carbon with trace Co and rich edge sites as highly efficient electrocatalyst for oxygen reduction reaction

Oxygen reduction reaction （ORR） is key to fuel cells and metal-air batteries which are considered as the al- ternative clean energy. Various carbon materials have been widely researched as ORR electrocatalysts. It has been ac- cepted that heteroatom doping and exposure of the edge sites can effectively improve the activity of carbon materials. In this work, we used a simple method to prepare a novel N, P-dual doped carbon-based catalyst with many holes on the surface. In addition, trace level Co doping in the carbon material forming Co-N-C active species can further enhance the ORR performance. On one hand, the doping can adjust the elec- tronic structure of carbon atoms, which would induce more active sites for ORR. And on the other hand, the holes formed on the surface of carbon nanosheets would expose more edge sites and can improve the intrinsic activity of carbon. Due to the heteroatom doping and the exposed edge sites, the pre- pared carbon materials showed highly excellent ORR perfor- mance, dose to that of commercial Pt/C.