Synthesis and electromagnetic absorption properties of micro-nano nickel powders prepared with liquid phase reduction method

Monodisperse micro-nano nickel powders have been prepared by chemical reduction of aqueous solution NiSO_(4),NaOH and NaH_(2)PO_(2),and the influence of pH value and initial concentration of NiSO_(4) on the size,structure,morphology and microwave absorption properties of nickel powders were investigated.The crystal structure of nickel powders was characterized by X-ray diffraction(XRD).And the morphology of the as-synthesized products was characterized by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The microwave absorption properties of the composite materials were characterized by network analyzer.The result indicates that the growth of nickel powders produced by NiSO_(4) and NaH_(2)PO_(2) at alkaline condition deeply relies on pH value and initial concentration of NiSO_(4) in reaction system.Different sizes of nickel powders with the diameter of 1.5μm and 180 nm were produced at the pH value of 10 and initial concentration of NiSO_(4) at 0.5 mol/L.The network analyzer showed definite microwave absorption properties of nickel powders with different sizes in the range of 0.5-18.0 GHz.

Performance and Mechanism Research of Au-HSTiO2 on Photocatalytic Hydrogen Production

In this paper,we report our attempts to raise the efficiency of liquid reduction method when using high specific surface area TiO2(HSTiO2)by doping Au.Characterization of Au-HSTiO2 was conducted via XRD,UV-vis,SEM,and photocurrent intensity.The experimental results show that Au-HSTiO2 exhibits prominently higher photocatalytic hydrogen production than TiO2 and HSTiO2.Enhanced photosynthetic hydrogen production ability of Au-HSTiO2 should be attributed to the presence of abundant surface active sites of HSTiO2,remarkably extending electronic holes in Au doping.This study provides a promising photosynthetic material for hydrogen production.

Physicochemical properties and antibacterial application of silver nanoparticles stabilized by whey protein isolate

Nano metal materials have been widely explored to be applied in medical,environmental,and material science.Among these nanoparticles,especially silver nanoparticles(AgNPs),have drawn increasing attention for antimicrobial applications.Most researchers are keen on the development of the biologically friendly capping reagents for the synthesis of AgNPs,instead of unfriendly organic polymers.In this study,the liquid chemical reduction method was used to synthesize AgNPs with edible whey protein isolate(WPI)as a capping reagent.These WPI-AgNPs had a broad size distribution(average diameter of 138.6 nm),and their dimensions could be readily controlled in the range of 22.5-149.6 nm by introducing different concentrations of chloride.Subsequently,it was confirmed that WPI-AgNPs were formed through two mechanisms,which were respectively reduced in situ(without the addition of NaCl)and ex situ(in presence of NaCl)to yield silver nanoparticles.The WPI-AgNPs synthesized in presence of 10 mM of NaCl as mediation reagent were stable at room temperature or 4℃ up to 3 months.Furthermore,the synthesized WPI-AgNPs had a good antibacterial activity toward pathogens including Gram-negative E.coli and Gram-positive S.aureus.The results shed light on method and capping reagent to stabilize silver nanoparticles,which highlighted the potential of WPI and chloride in metal nanoparticle synthesis.