Targeted Synthesis Conditions of Layered Bismuth Oxychalcogenides Via Electrochemical Phase Diagrams

We investigated how density functional theory calculations of electrochemical stability can guide the experimental hydrothermal synthesis of bismuth oxychalcogenides. The target phases, which are layered thermoelectrics and exhibit electronic anisotropy, represent exciting materials for catalysis, photoluminescence, and energy applications. We coupled experimental synthesis with DFT-calculated multielement Pourbaix diagrams to identify target pH and potential synthesis regions that ultimately proved successful. We further investigated numerous degrees of freedom present in the reaction, such as mass ratio of reactants, temperature, and concentration of ions, to qualitatively understand how changes in the chemistry of the oxychalcogenides alter phase stability. Last we discuss how these materials can be driven towards target phase production.