| Design,synthesis and utilization of nanomaterials have a good prospect in energy efficient utilization and environmental protection.Among multitudinous systems,due to their unique photoelectric properties,easy modification,good biocompatibility and catalytic performance,noble metal nanostructures have many potential applications in the fields of catalysis,sensors,surface-enhanced Raman spectroscopy.For the process of NOx reduction,nitrophenol reduction and organic synthesis,Gold nanoparticles have highly catalytic activity and their catalytic performance is directly related to their size,morphology and dispersion.Au NPs are prone to irreversible aggregation in solution,which greatly reduces the catalytic activity due to the van der Waals force and high surface energy.Graphene oxides have a large specific surface area,excellent load capacity and a high capacity for nanoparticles,making it a good carrier for dispersing and stabilizing metal nanoparticles.Moreover,GO has a strong adaptability to changes in the volume during the reaction process,which shows unique advantages in loading Au NPs.The strong synergistic effect between Au NPs and GO can improve the catalytic performance,and the strong covalent interface between them can also significantly reduce the toxicity of the catalyst.(1)The Spherical gold nanoparticles were synthesized on the surface of GO nanosheet by ultrasonic assisted in situ seed mediation method which serve as seeds,and the two-dimensional bone-like gold nanoplates/GO composites were synthesized in the growth fluid from these seeds.The morphology,composition and structure of the composites were characterized.The results showed that the gold nanoparticles prepared by this method were bone-like and two-dimensional nanoplates,uniform size,aspect ratio of about 1.6,and uniform dispersion on Go nanosheets.XRD analysis shows that the Au nanoplates is of Face-centered cube structure.Raman and XPS indicated the composition of the composites and the oxygen-containing groups on the GO surface were consumed during the overgrowth of gold nanoparticles,and covalent chemical bonds were formed between them.(2)The Cocoon-like gold nanoparticle/GO composite was synthesized by using silver assisted seed mediation method and chemical reduction method,which use cetyltrimethylammonium bromide(CTAB)as the structure guiding agent and ascorbic acid(AA)as the weak reducing agent.SEM and TEM results showed that the former method synthesized uniform silkworm cocoon Au NPs with aspect ratio between1.3-1.6 on the surface of GO.Raman analysis showed that the D peak decreased significantly and the defects were reduced.XPS indicated that the composites surface contained Au(0)and the oxygen-containing functional groups were significantly reduced,likewise,a covalent chemical bond was formed between them.(3)The catalytic reduction of 4-NP to 4-AP is used to evaluate the catalytic performance of gold nanoparticles.The results showed that the two kinds of composites have good catalytic activity,the two-dimensional bone-like gold nanoplates/GO composites can be fully completed the catalytic degradation process within 10 min,the catalytic rate constant is 0.0896 m M/min,and the reusability relatively stable within 6 cycles;However,the cocoon-like gold nanoparticles /Go could not completely complete the degradation process within 10 min,and the catalytic rate constant was 0.0808 m M/min.Therefore,the former had higher catalytic activity.Figure [28] table [8] reference [102]... |
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