Moderate temperature sulfurization and selenization of highly stable metal oxides: an opportunity for chalcogenide perovskites

Oxide perovskites would provide a convenient precursor for the synthesis of chalcogenide perovskites. However, the stability of oxide perovskites means that there is no driving force for sulfurization or selenization with conventional chalcogen sources. In this work, we show that sulfurization and selenization of highly stable early transition metal oxides are possible by heating in the presence of HfH2 and S or Se, thereby creating HfS3 or HfSe3 as an oxygen sink and producing an oxygen shuttle in the form of H2O/H2S or H2O/H2Se. The conversion of ZrO2 into ZrS3 or ZrSe3 is supported with thermodynamic calculations and demonstrated experimentally as a proof-of-concept. Subsequently, we demonstrate that BaZrO3 can be converted to BaZrS3 at 575 degrees C, several hundred degrees below previous methods relying on conventional sulfur sources. We report the conversion of BaZrO3 into BaZrS3 at temperatures below 600 degrees C, enabled by a thermodynamics-guided redesigned of the sulfurization process.