Self-assembled flower-like microstructure in Zn_(1-x)Cd_xO nanoparticles

The structural and optical characterization of cadmium-doped zinc oxide nanoparticles synthesized by precipitation method was studied.X-ray diffraction study confirmed the substitution of cadmium dopant without disturbing the basic wurtzite structure of zinc oxide.The average crystalline size,lattice constants and unit cell volume also increased up to4%of cadmium doping.Energy gaps of the samples were determined from the ultraviolet?visible absorption spectrum as well as Tauc’s plot which infers that the energy gap decreases with the increase of cadmium content.Fourier transformation infrared spectrum confirms the cadmium dopant through peak shifting from485to563cm?1.Photoluminescence spectrum also defines the cadmium dopant by intensity increase.The broad Raman peak at437cm?1indicates that the wurtzite structure of zinc oxide is weakened by5%cadmium doping.Field emission scanning electron microscope study also confirms the existence of particles in nanometer size and it indentifies the microstructure transformation from nanoparticles to jasmine flower-like structure on5%cadmium doping.

Core-shell particles of C-doped CdS and graphene: A noble metal-free approach for efficient photocatalytic H_(2) generation

To achieve efficient photocatalytic H_(2) generation from water using earth-abundant and cost-effective materials,a simple synthesis method for carbon-doped CdS particles wrapped with graphene(C-doped CdS@G)is reported.The doping effect and the application of graphene as cocatalyst for CdS is studied for photocatalytic H_(2) generation.The most active sample consists of CdS and graphene(CdS-0.15G)exhibits promising photocatalytic activity,producing 3.12 mmol g^-(1) h^-(1) of H_(2) under simulated solar light which is^4.6 times superior than pure CdS nanoparticles giving an apparent quantum efficiency(AQY)of 11.7%.The enhanced photocatalytic activity for H_(2) generation is associated to the narrowing of the bandgap,enhanced light absorption,fast interfacial charge transfer,and higher carrier density(N_(D))in C-doped CdS@G samples.This is achieved by C doping in CdS nanoparticles and the formation of a graphene shell over the C-doped CdS nanoparticles.After stability test,the spent catalysts sample was also characterized to investigate the nanostructure.

Real-time fluorescent detection of food spoilage with doped quantum dots-anchored hydrogel sensor

Spermine assumes a pivotal role in assessing food safety due to its potential to induce a spectrum of diseases upon excessive consumption.However,contemporary spermine detection methodologies,exemplified by high-performance liquid chromatography(HPLC),demand costly instrumentation and the expertise of skilled technicians.To address this challenge,the study introduces a portable fluorescence sensing platform.Ratiometric fluorescent probes were realized through the utilization of CdS quantum dots deeply doped with Ag^(+)(CdS:Ag QDs)and nitrogen-doped carbon quantum dots(N-CQDs).Hydrogen bonds formed between CdS:Ag QDs and spermine result in the formation of the assembly and the decreasing of the fluorescence intensity.In an effort to broaden the applicative scope and streamline deployment processes,fluorescent sensing hydrogels were meticulously engineered,capitalizing on the swelling properties inherent in polyvinyl alcohol(PVA)hydrogels.The systematic delineation of the correlation between 1-R/B and spermine concentration facilitates the quantitative determination of spermine concentration.The incorporation of this composite construct serves to alleviate environmental influences on the probes,thereby augmenting their precision.The portable fluorescent sensing platform proves pivotal in expeditiously measuring spermine concentration within the fluorescent sensing hydrogel,enabling a quantitative assessment of pork freshness.The utilization of this platform for food freshness evaluation imparts the benefits of convenience,cost-effectiveness,and intuitive operation.