A facile method for preparing nickel hydroxyl nanoparticles loaded graphene aerogels has been established. The prepared aerogels were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and Raman spectroscopy. Their applications as absorbents or electrode materials for supercapacitors were investigated. They showed excellent performance on the absorption of different dyes. The absorption capacities ranged from 202 to 513 mg g–1. They also displayed high absorption capacities toward oils and organic solvents. The aerogels demonstrated high capacitance and stability as electrode materials of supercapacitors. The specific capacitance reached 702 F g–1 at current densities of 1 A g–1.

The ecological and environmental damage resulting from oil pollution is an area of great concern. Biocompatible porous monoliths based on polylactic acid (PLA) modified with reduced graphene oxide (rGPLA) as effective oil sorbent were prepared by freeze-drying. The porous monoliths were characterized by scanning electron microscopy and X-ray diffraction. Their physical properties including water contact angles, compressive strengths and moisture absorption were investigated. The incorporation of reduced graphene oxide (rGO) increased the hydrophobicity of the rGPLA porous monoliths resulting in highly selective absorption for oil. In addition, the use of rGO increased the compressive strength of the porous monoliths so they could be recycled. These porous rGPLA monoliths are green biodegradable efficient absorbents that should be useful for the treatment of oil spills.

A simple method to fabricate Bi nanoparticles by using redox reactions between sodium borohydride and ammonium bismuth citrate in the presence of soluble starch in water phase was developed. The results show that soluble starch is better than PVP in stabilizing Bi nanoparticles. The as-prepared Bi nanoparticles were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, energy-dispersive X-ray, and powder X-ray diffraction. The catalytic performance of the Bi nanoparticles for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of sodium borohydride was studied. The effects of sodium borohydride concentration, initial 4-NP concentration, catalyst dose, and reduction temperature were also investigated.

Inspired by photonic nanostructures in nature, such as the hair-like chaetae on the body of sea mice, inverse opal photonic crystals films were fabricated with chitosan, a kind of biomacromolecule found in nature. First, monodispersed polystyrene (PS) colloidal crystal templates with different particle sizes were prepared. The inverse opal films (IOFs) were fabricated through in situ cross-linking of the PS templates. The IOFs contain periodically ordered interconnecting pores that endow the films with photonic stop bands and structural colors, which are visible to the naked eye. The IOFs exhibit rapid reversible changes in their structural colors and reflectance peaks in response to alcohols and phenols. Possible mechanisms for the shifts in the IOF’s reflectance peaks are proposed. The changes in the IOFs in response to alcohols and phenols provide a potential way to visually detect these organic solvents.

An environment-friendly approach to synthesizing reduced graphene oxide (RGO) was developed by using chitosan (CS) as both a reducing and a stabilizing agent. Factors that affect the reduction of graphene oxide (GO), such as the ratio of CS/GO, pH and temperature, were explored to obtain optimum reaction conditions. The RGO was characterized with UV visible absorption spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction spectroscopy, thermo-gravimetric analysis, and X-ray photoelectron spectroscopy and transmission electron microscopy. Analysis shows that CS macromolecules can efficiently reduce GO at a comparatively low temperature and their adsorption onto the RGO nanosheets allows a stable RGO aqueous dispersion to be formed. Since CS is a natural, nontoxic and biodegradable macromolecule, this approach provides a new green method for GO reduction that would facilitate the large scale production of RGO, which has great value for graphene applications. Moreover, CS can reduce GO and AgNO3 (or HAuCl4) in one pot to obtain Ag nanoparticle-RGO hybrids or Au nanoparticle-RGO hybrids that exhibit good electrochemical activity.

Polyvinyl alcohol (PVA) hydrogels have been proposed for use as promising biomaterials in biomedical and tissue engineering but their poor mechanical and water-retention properties have hindered their development. Graphene oxide (GO), an excellent nanofiller, was added to PVA to make GO/PVA composite hydrogels by a freeze/thaw method. The mechanical properties of the GO/PVA hydrogels were significantly improved. Compared to pure PVA hydrogels, a 132% increase in tensile strength and a 36% improvement of compressive strength were achieved with the addition of 0.8 wt% of GO, which suggests an excellent load transfer between the GO and the PVA matrix. The incorporation of certain amount of GO into composite hydrogels does not affect the toxicity of PVA to osteoblast cells.

Polyvinyl alcohol (PVA) hydrogels have been proposed for use as promising biomaterials in biomedical and tissue engineering but their poor mechanical and water-retention properties have hindered their development. Graphene oxide (GO), an excellent nanofiller, was added to PVA to make GO/PVA composite hydrogels by a freeze/thaw method. The mechanical properties of the GO/PVA hydrogels were significantly improved. Compared to pure PVA hydrogels, a 132% increase in tensile strength and a 36% improvement of compressive strength were achieved with the addition of 0.8 wt% of GO, which suggests an excellent load transfer between the GO and the PVA matrix. The incorporation of certain amount of GO into composite hydrogels does not affect the toxicity of PVA to osteoblast cells.