Mechanochemical synthesis and reactivity of PbS nanocrystals

PbS nanocrystals using surfactant assisted mechanochemical synthesis have been prepared by co-milling of lead acetate (CH3COO)2Pb3H2O and sodium sulfide Na2S9H2O. The methods of XRD, FE-SEM, TEM (HRTEM), UV–vis, specific surface area measurements as well as reactivity in acidic FeCl3 media were used for the nanocrystals characterization. The XRD patterns confirmed the presence of galena PbS (JCPDS 5-592) whatever treatment conditions were applied. The strong observable peaks indicate the highly crystalline nature in formation of PbS nanostructures where preferential crystal growth in the (2 0 0) direction after addition of ethylenediamine (EDA), sodiumdodecylsulphate (SDS) and ethylendiaminetetraacetic disodium salt dihydrate (EDH) surfactants has been observed. The surface weighted crystallite sizes 3, 8, 11 and 19 nm have been calculated from XRD data using the Warren–Averbach method for surfactant-free and/or EDA, SDS and EDH surfactants assisted mechanochemical synthesis. The leaching rate of galena PbS in acidic FeCl3 solution has been studied. The dependence of PbS nanocrystals reactivity on preferential growth parameter is documented. The highest value of the specific rate constant of leaching, k0/SA has been obtained for the mechanochemically synthesized PbS in presence of EDH surfactant.

► PbS nanocrystals synthesis by co-milling of lead acetate and sodium sulphide precursors.
► The preferential crystal growth in the (2 0 0) PbS direction after addition of selected surfactants.
► PbS nanocrystals reactivity depends on the preferential growth parameter.