A facile and environment friendly approach to synthesis of unique hierarchical BiOCl flowery microspheres(FMs)using a biodegradable surfactant polyvinyl alcohol(PVA)was reported herein for the first time.Compared to the BiOCl nanosheets synthesized in the absence of PVA,hierarchical BiOCl FMs consist of large amounts of interwoven polycrystalline nanosheets that assemble into a porous flowery structure.The formation mechanism of the hierarchical BiOCl FMs was also proposed,whereby PVA was believed to play a key role in the crystal growth and the formation of the final microstructures.Compared with TiO2-P25 and BiOCl nanosheets,hierarchical BiOCl FMs displayed remarkably enhanced photocatalytic activity,and20 mg of BiOCl FMs could completely degrade 50 mL of methyl orange solution(20 mg/L)within 30 min under UVlight irradiation.According to the comprehensive analysis,it can be concluded that the larger specific surface area,porosity,suitable band gap,and the enhanced light absorption capacity may contribute to the remarkably enhanced photocatalytic activity.This facile and green approach to fabricating hierarchical BiOCl FMs would give vital clues to develop new route for synthesizing other hierarchical structured materials.
Ni-Ag/TiC composite coating was prepared on the 45 steel substrates by means of laser cladding. Microstructure and wear properties of composite coatings were analyzed using optical microscopy, field emission scanning electron microscopy and wear machine. The experimental results show that defects, such as cracks and pores, do not occur in the laser-cladded Ni-Ag/TiC composite coating and 45 steel substrate, and they present good metallurgical bonding between them. Compared with Ni/TiC composite coating, micro- hardness values of the two coatings do not present evident differences. The wear experiment result shows that Ni-Ag/TiC composite coated with Ag possesses low friction coefficient and good wear resistance compared with Ni/TiC composite coating.
A novel glucose biosensor based on graphene nanosheets(GNs)modified gold nanowire arrays(AuNWAs)electrode was constructed.Highly ordered gold nanowire arrays were prepared by direct electrodeposition in anodic aluminum oxide templates.GNs were synthesized through a public route involving graphite oxidation,exfoliation,and chemical reduction.Field emission scanning electron microscope and high-resolution transmission electron microscope were employed to characterize the asprepared AuNWAs and GNs.Glucose oxidase was immobilized on the surface of GNs-AuNWAs modified electrode via a cross-linking method.The cyclic voltammetry results showed that the GNs-AuNWAs-based glucose biosensors have high catalysis activity to hydrogen peroxide(H2O2)than those modified with GNs or AuNWAs only.Furthermore,amperometric response was employed to detect glucose concentration owing to its simplicity,high selectivity,and relative low cost.Glucose biosensors based on GNs-AuNWAs showed excellent performance with high sensitivity of 40.25 lA cm-2(mmol/L)-1,low detection limit of 0.02 mmol/L,and a linear range from 0.02 to 3 mmol/L.
