Dhanapalan Karthikeyan

Facile synthesis of zinc oxide nanoparticles decorated graphene oxide composite via simple solvothermal route and their photocatalytic activity on methylene blue degradation.

Zinc oxide nanoparticles decorated graphene oxide (ZnO@GO) composite was synthesized by simple solvothermal method where zinc oxide (ZnO) nanoparticles and graphene oxide (GO) were synthesized via simple thermal oxidation and Hummers method, respectively. The obtained materials were thoroughly characterized by various physico-chemical techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Raman spectrum shows the intensity of D to G value was close to one which confirms the obtained GO and ZnO@GO composite possesses moderate graphitization. TEM images shows the ZnO nanoparticles mean size of 15±5nm were dispersed over the wrinkled graphene layers. The photocatalytic performance of ZnO@GO composite on degradation of methylene blue (MB) is investigated and the results show that the GO plays an important role in the enhancement of photocatalytic performance. The synthesized ZnO@GO composite achieves a maximum degradation efficiency of 98.5% in a neutral solution under UV-light irradiation for 15min as compared with pure ZnO (degradation efficiency is 49% after 60min of irradiation) due to the increased light absorption, the reduced charge recombination with the introduction of GO. Moreover, the resulting ZnO@GO composite possesses excellent degradation efficiency as compared to ZnO nanoparticles alone on MB.

Synthesis, characterization, and antiproliferative and apoptosis inducing effects of novel s-triazine derivatives

In an attempt to design and synthesize a new class of antitumor agents, a mild and eco-friendly protocol for nucleophilic substitution using an s-triazine scaffold, via amine and Schiff base derivatives, has been developed. In order to obtain antitumor activity, all synthesized compounds were screened in vitro for their cytotoxicity against human fibrosarcoma tumor cells (HT-1080) and a cervical cancer cell line (HeLa), for their ability to inhibit the growth of cancer cells. The selected s-triazine analogs (5c, 5d, and 6c) have been preliminarily studied for their reactive oxygen species (ROS) properties, mitochondrial membrane potential (MMP) and apoptosis (AO/EtBr) activity against the HT-1080 cancer cell line. The in vitro anticancer activity analysis has revealed that the synthesized compounds have good/moderate inhibitory activity against the tested cell lines compared to the standard drug. The theoretical study results also provide evidence that the s-triazines scaffolds have been successfully identified as superior p53-MDM2 inhibitors through structure-based design.

Effect of metal content on the activity and product selectivity of n -decane hydroisomerization over Ni-Pd/HY zeolite

Metal-loaded zeolite catalysts were synthesized and examined in the hydroisomerization of n -decane. Specifically, zeolite Y was impregnated with 0.1 wt% Pd and varying amounts of Ni (0.1-0.5 wt%). The crystallinity of the metal-loaded catalysts was characterized by X-ray diffraction, and the average metal particle size was determined by transmission electron microscopy. The states of Pd and Ni were identified by X-ray photoelectron spectroscopy. Ammonia temperature-programmed desorption analysis revealed the occurrence of ion-exchange of some of the catalyst acid sites with Ni 2+ . The reducibility of the HY zeolite-supported Pd, Ni, and Pd-Ni catalysts was studied by temperature-programmed reduction. The hydroisomerization of n -decane over the prepared catalyst was conducted at 200-450 °C under 1 atm. Ni addition of up to 0.3 wt% over 0.1 wt% Pd/HY enhanced the n -decane conversion and isomerization product selectivity. The improved selectivity of the mono- and dibranched isomers suggested the occurrence of a protonated cyclopropane intermediate mechanism. However, further Ni addition above 0.3 wt% considerably reduced the activity and isomerization selectivity. The bimetallic catalysts were more selective toward the formation of dibranched isomers, i.e., those containing a higher octane number.