Controlled growth of pyrite FeS2 crystallites by a facile surfactant-assisted solvothermal method

A simple surfactant-assisted ethylene glycol-mediated solvothermal method is reported for thesynthesis of pyrite crystallites with cubic and octahedral shapes for the first time. The process involvedthe reduction of sulfur and the reaction between S2 and Fe2+in the presence of surfactant. By changingthe concentration of NaOH and properly adjusting some other experimental parameters, pyritecrystallites with a defined crystalline structure have been realized. It was demonstrated that the differentsurfactants can adsorb on certain faces selectively, the subsequent competing growth between [100] and[111] directions directed the final shape of the particles. NaOH was found to be crucial for theformation of the pyrite cubes and octahedral crystallites by not only acting as the pH regulator but alsodetermining the reduction ability of ethylene glycol. The influences of solvothermal temperature, thedosage of sulfur, the concentration of NaOH and the kinds of the surfactants on the shape of thecrystallites were investigated systematically. The magnetic properties were also studied. Moreover, themethod demonstrated here could be of great potential for controlling the synthesis of other metalchalcogenides with controlled shapes and structures.