Economically synthesized NiCo2S4/TiO2 with high reflectance ability as the counter electrode to replace Pt for dye-sensitized solar cells

Core-shell composite nanoarchitectonics of TiO2@NiCo2S4 via thermal decomposition approach for photodegradation of congo red

In the present work, TiO2@NiCo2S4 core-shell nanocomposites have been successfully synthesized using a thermal decomposition approach using nickel acetyl acetonate and cobalt acetyl acetonate as metal salts and thiourea as source of sulfur in the presence of TiO2 microspheres in diphenyl ether at about 200 °C in air aiming at their application in photodegradation of congo red (CR), a dye pollutant. The thickness of NiCo2S4 nanoparticles (shell) could be varied using different concentrations of reagents. Various analytical techniques were used to characterize the TiO2@NiCo2S4 core-shell nanocomposites including powder XRD, FE-SEM, XPS, TEM and EDX confirming their successful synthesis. The synthesized core-shell nanocomposites exhibit notable photocatalytic activity towards degradation of an aqueous solution of congo red under sunlight. The photocatalytic degradation efficiency of TiO2@NiCo2S4 nanocomposites is better than that of TiO2-based nanocomposites, metal sulfide nanoparticles and other nanocomposites reported in the literature.

CuCo2S4 nanoparticles synthesized via a thermal decomposition approach: evaluation of their potential as peroxidase mimics

The current study demonstrates the synthesis of CuCo2S4 nanoparticles using a novel thermal decomposition approach. The CuCo2S4 nanoparticles were synthesized under various conditions by changing the source of sulfur and the solvent. The CuCo2S4 nanoparticles were characterized using an array of analytical techniques. Powder XRD results indicate the successful formation of CuCo2S4 nanoparticles. TEM results show agglomerated nanoparticles with close to spherical morphology and XPS measurements indicate the presence of Cu2+, Cu+, Co3+, Co2+, and S2- in the samples. The CuCo2S4 nanoparticles exhibit weak ferromagnetic and paramagnetic behaviour at 5 K and 300 K, respectively. The CuCo2S4 nanoparticles were explored for their enzyme mimetic activity using 3,3',5,5' tetramethylbenzidine (TMB) as a substrate. They exhibit better catalytic activity compared to that of a natural enzyme (horseradish peroxidase) and other metal sulfide nanoparticles reported in the literature.