Reprogramming Impurity States from Carrier-Loss Centers to Electron-Relay States in Single-Atom Photocatalysts

Area of Science:

• Materials Science
• Photocatalysis
• Nanotechnology

Background:

• Single-atom modification in semiconductor photocatalysts creates active sites but often leads to carrier loss via impurity states and nonradiative recombination.
• Impurity-state charge localization governs trapped photoelectron behavior, critically impacting charge utilization in single-atom photocatalysts.

Purpose of the Study:

• To investigate the role of impurity-state charge localization in single-atom photocatalyst performance.
• To develop a strategy for reprogramming impurity states to enhance charge utilization and photocatalytic efficiency.

Main Methods:

• Constructed asymmetric O-Cu-B coordination in (Cu-O/B)TiO2 by introducing Boron (B) hetero p-orbital ligands.
• Utilized photophysical analyses to assess trap-mediated nonradiative loss.
• Employed light-field-assisted dynamic computation to visualize carrier redistribution.

Main Results:

• Delocalized Cu-related impurity states through multicenter orbital hybridization, converting localized trap centers into electron-relay states.
• Achieved a near-unity apparent quantum efficiency of 94.7% for the engineered (Cu-O/B)TiO2 photocatalyst.
• Observed a 2.8-fold enhancement in hydrogen (H2) evolution compared to the control (Cu-O)TiO2.

Conclusions:

• Delocalizing impurity states effectively reduces carrier loss and enhances photocatalytic activity.
• Nanoscale coordination engineering offers a viable route to reprogram impurity states for efficient single-atom photocatalysis.
• The study highlights the importance of controlling charge localization for optimizing photocatalyst performance.