Synthesis and Formation Mechanism of La2O2S via a Novel Solvothermal Pressure-Relief Process

A new solvothermal pressure-relief (SPR) process was successfully developed for synthesis of La2O2S at relatively low temperature (300 °C) by using La(NO3)3·nH2O and NH2CSNH2 as reactants in organic media. In contrast, the normal solvothermal and hydrothermal process can only produce La(OH)CO3 and La(OH)SO4, respectively. The present SPR process provides a favorable low-temperature reaction pathway for synthesis of lanthanide oxysulfides. The mechanism and solvent effects on the formation of lanthanum oxysulfide were investigated.