Formation of iron sulfide photocatalytic colloidal dispersion via pulsed laser ablation in liquids

Abstract

Pulsed laser irradiation of iron sulfide in water and ethanol allows laser ablation and generation of FeS nano/micro particles. Measurement of the size distribution reveals 100, 1000 and 5000 nm sized particles in water and 180 nm sized particles in ethanol. The values of zeta potential: 13.2 mV for colloid in water confirm incipient stability and tendency for coagulation whereas the value: -40.6 mV shows good stability of ablatively achieved nanoparticles in ethanol. SEM analyses of particles obtained by evaporation of solvents on Ta substrate revealed shapeless, roundshape and sheet-like morphology of agglomerates whose size span from units up to tens of µm. Also spherical particles sized around tens of nm were detected. EDX shows Fe/S ratio ∼3.25 and ∼ 1.2 for particles ablated in water and ethanol respectively. Raman spectroscopy indicates the formation of mackinawite (Fe_1+xS) and pyrrhotite (Fe_1-xS) phase. The photocatalytic effect of prepared water colloid was tested in methylene blue (MB) degradation under the daylight.