Cover Feature: Redox Properties of Iron Sulfides: Direct versus Catalytic Reduction and Implications for Catalyst Design (ChemCatChem 12/2022)

Abstract

The Cover Feature shows two different natural sceneries where iron sulfides play a key role in mediating chemical reductions. One where the reactions are catalytic, nitrogenase and another where the chemical reduction is direct, hydrothermal vents. The two reactions are sometimes confused. In their Research Article, C. F. Garibello et al. explore the relationship between direct and catalytic reduction of nitrite to ammonia using a “test set” of iron sulfide materials, including amorphous irons sulfide, greigite, pyrite and troilite. XAS results show the changes in the structure of the materials after reaction, and the ammonia quantification allows us to explore the selectivity of reduction products. Amorphous iron sulfide shows the greatest selectivity for NH3/NH4+ production as both a direct reductant and a catalyst, while the most stable minerals (troilite and pyrite) show the largest differences between catalytic and direct reduction. More information can be found in the Research Article by C. F. Garibello et al.