Support Amorphization Engineering Regulates Single-Atom Ru as an Electron Pump for Nitrogen Photofixation

Single-atom photocatalysts exhibit great potential for converting solar energy into value-added chemicals or fuels, but the insufficient efficiency of charge transfer from light-absorbed units to single-atom catalytic sites limits the overall photocatalytic performance. Herein, we developed an amorphization strategy of ferric oxide support to accelerate the enrichment of photogenerated electrons to single-atom Ru for enhanced nitrogen photofixation. The ammonia yield rate of Ru single atoms distributed on amorphous ferric oxide nanosheets (Ru1/2DAF) in pure water reached 213 μmol·gcat.–1·h–1, even four times higher than that of the crystalline counterpart. Mechanistic studies indicated that the amorphous structure could efficiently modulate the electronic density of states to reduce the electron-transfer energy barrier and guide electrons from amorphous support to Ru 4d orbitals via d(Ru)–d(Fe) coupling. This work provides fresh insights on the design of single-atom photocatalysts and emphasizes the importance of the charge transfer behavior in tuning the catalytic activity.