Layered nanocomposite of zinc sulfide covered reduced graphene oxide and their implications for electrocatalytic applications

Herein, we have synthesized zinc sulfide nanospheres (ZnS NPs) encapsulated on reduced graphene oxide (RGO) hybrid by an ultrasonic bath (50 kHz/60 W). The physical and structural properties of ZnS NPs@RGO hybrid were analyzed by TEM, XRD, EIS and EDS. As-prepared ZnS NPs@RGO hybrid was applied towards the electrochemical determination of caffeic acid (CA) in various food samples. The ZnS NPs@RGO hybrid modified electrode (GCE) exhibited an excellent electrocatalytic performance towards caffeic acid detection and determination, when compared to other modified electrodes. Therefore, the electrochemical sensing performance of the fabricated and nanocomposite modified electrode was significantly improved owing to the synergistic effect of ZnS NPs and RGO catalyst. Furthermore, the hybrid materials provide highly active electro-sites as well as rapid electron transport pathways. The proposed electrochemical caffeic acid sensor produces a wide linear range of 0.015–671.7 µM with a nanomolar level detection limit (3.29 nM). In addition, the real sample analysis of the proposed sensor has applied to the determination of caffeic acid in various food samples.     

Utilization of photocatalytic ZnO nanoparticles for deactivation of safranine dye and their applications for statistical analysis

A soft chemical solution process was used in synthesis of photocatalytic zinc oxide nanoparticles (ZnO-PNPs) at low temperature. The synthesized PNPs were characterized in terms of their crystallinity, morphological, catalytic, spectroscopic and statistical analysis techniques. X-ray powder diffraction patterns (XRD) were used to know the crystalline property of the prepared materials whereas field emission electronic microscopy (FESEM) was employed to observe the morphology of grown NPs. UV–visible spectroscopy was employed to analyze the absorbance of degraded safranine (SA) dye in presence of NPs at desired time interval. Parameters of statistical analysis give necessary information for established analytical procedures to ensure quality and purity of results. With the help of this analytical method, outcomes were calculated in terms of absorbance such as standard deviation (SD), relative standard deviation (RSD), etc. at 95% confidence level. The photocatalytic deactivation/degradation process significantly enhanced the activity of ZnO-PNPs under UV–visible light in presence of SA dye. The effective concentration of used PNPs was optimized and validated via standard analytical procedure, which exhibited greater significance on deactivation process. The absorption spectra of photocatalyzed solution and activity of ZnO-PNPs were compared with those of pure ZnO, obtained by UV–visible spectroscopy.     

Sonochemical synthesis and fabrication of neodymium sesquioxide entrapped with graphene oxide based hierarchical nanocomposite for highly sensitive electrochemical sensor of anti-cancer (raloxifene) drug

The ultrasound-assisted synthesis of a novel neodymium sesquioxide nanoparticles (Nd₂O₅ NPs) decorated graphene oxide (GO) nanocomposite under ultrasonic probe (Ultrasonic processor model-PR 1000; frequency-30 kHz; power of 100 W/cm²) has been reported. After then, SEM, TEM, XRD, EDX and electrochemical impedance spectroscopy characterized was analyzed using Nd₂O₅ NPs@GO nanomaterial. Furthermore, the nanomaterial modified GCE (glassy carbon electrode) shows excellent electrochemical sensing performance towards anti-cancer drug. Raloxifene is one of the important anti-cancer drug. Moreover, the fabricated electrochemical sensor has showed a wide linear range for raloxifene between 0.03 and 472.5 µM and nanomolar detection limit (18.43 nM). In addition, the Nd₂O₅ NPs@GO modified sensor has been applied to the determination of raloxifene in human blood and urine samples.