This talk will discuss our recent efforts to develop ternary metal halide nanocrystals for applications in photocatalytic CO2 reduction. We have synthesized ternary AgBr1-xIx nanocrystals of controlled composition, crystal structure, and morphology. The different crystal structures of the end member phases, where pure AgBr is rock salt while pure AgI is wurtzite, lead to limited thermodynamic solid solubility of the two compounds. Through kinetic control of the growth process we have achieved solid solutions of AgBr1-xIx nanocrystals that are not predicted by the equilibrium phase diagram. Bromide-rich AgBr1-xIx nanocrystals possess the rock salt crystal structure. The nanocrystal shape changes with iodide content to form either cuboctahedron with mixed {100} and {111} faceting or platelets with mixed {111} and {110} faceting. Iodide-rich AgBr1-xIx nanocrystals possess the wurtzite crystal structure with mixed {1-100} and {0001} faceting forming hexagonal platelets. Other silver halide nanocrystals, such as AgCl and AgBr nanocubes, have shown good activity for the photocatalytic conversion of CO2 to methanol and ethanol. The ability to systematically tune the composition, crystal structure, and crystal habit of these ternary AgBr1-xIx nanocrystals provide a model system to study structure-property relationships in new photocatalytic materials.

Solid-state chemistry of ternary metal halide nanocrystals

251st National Meeting (2016)

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