Photocatalytic Activity of Nickel Sulfide Composite Powders Synthesized by Solution Combustion Method

Nickel sulfide composite powders were prepared through solution combustion synthesis using nickel nitrate as both nickel source and oxidant, together with various amounts of mixed urea-thiourea fuels. The precursor solutions were ignited by conventional and microwave heating. The combustion reaction behavior, phase structure and optical properties were analyzed as a function of fuel amounts. The combusted powders were composed of α-NiS, NiS2, Ni3S2 and NiO phases related to the fuel content and heating mode. The higher combustion temperature in microwave heating led to the oxidation of sulfide phase to nickel oxide. The highest amount of NiS phase with the maximum removal efficiency of methylene blue (MB) (∼ 52%) was achieved when conventional synthesis procedure with a urea to thiourea molar ratio of 2:0.75, was employed.