Three-dimensional graphitic carbon sphere foams as sorbents for cleaning oil spills

Frequent offshore oil spill accidents, industrial oily sewage, and the indiscriminate disposal of urban oily sewage have caused seri- ous impacts on the human living environment and health. The traditional oil-water separation methods not only cause easily environmental secondary pollution but also a waste of limited resources. Therefore, in this work, three-dimensional (3D) graphitic carbon sphere (GCS) foams (collectively referred hereafter as 3D foams) with a 3D porous structure, pore size distribution of 25-200 μm, and high porosity of 62vol% were prepared for oil adsorption via gel casting using GCS as the starting materials. The results indicate that the water contact angle (WCA) of the as-prepared 3D foams is 130°. The contents of GCS greatly influenced the hydrophobicity, WCA, and microstructure of the as-prepared samples. The adsorption capacities of the as-prepared 3D foams for paraffin oil, vegetable oil, and vacuum pump oil were approximately 12-15 g/g, which were 10 times that of GCS powder. The as-prepared foams are desirable characteristics of a good sorbent and could be widely used in oil spill accidents.

NiCoP/NiOOH nanoflowers loaded on ultrahigh porosity Co foam for hydrogen evolution reaction under large current density

Developing user-friendly electrodes for efficiently producing hydrogen from water to substitute non-renewable fossil fuels is one of the challenges in the hydrogen energy field.For the first time,we have prepared self-supporting ultrahigh porosity cobalt foam loaded with NiCoP/NiOOH nanoflowers(NiCoP/CF)via freeze-drying and phosphorization.The as-prepared hierarchical NiCoP/CF electrodes showed superior catalytic activity for hydrogen evolution reaction(HER)in alkaline media.The one resulted from phosphorization at 350℃(NiCoP/CF-350)only required overpotential of-47,and-126 mV to deliver geometrical current density of-10 mA cm^(-2) and-100 mA cm^(-2),respectively,demonstrating improved catalytic activity than the electrodes prepared using a commercial nickel foam as a support.Moreover,it could retain its superior stability at a current density higher than-500 mA cm^(-2) for 16 h.Such an outstanding performance can be attributed to the ultrahigh porosity of Co foam support,optimal adsorption energies of HER intermediates(H^(*)),facile water dissociation on the NiCoP/NiOOH heterointerfaces,and the assistance of NiOOH facilitating the electrons transfer from the Co foam inside to the NiCoP outside.The work would provide a new strategy for future design of advanced HER electrocatalysts.