Fe─S Bond‐Mediated Efficient Electron Transfer in Quantum Dots/Metal‐Organic Frameworks for Boosting Photoelectrocatalytic Nitrogen Fixation

Abstract Effective electron supply to produce ammonia in photoelectrochemical nitrogen reduction reaction (PEC NRR) remains challenging due to the sluggish multiple proton‐coupled electron transfer and unfavorable carrier recombination. Herein, InP quantum dots decorated with sulfur ligands (InP QDs‐S 2− ) bound to MIL‐100(Fe) as a benchmark catalyst for PEC NRR is reported. It is found that MIL‐100(Fe) can combined with InP QDs‐S 2− via Fe─S bonds as bridge to facilitate the electron transfer by experimental results. The formation of Fe─S bonds can facilitate electron transfer from inorganic S 2− ligands of InP QDs to the Fe metal sites of MIL‐100(Fe) within 52 ps, ensuring a more efficient electron transfer and electron‐hole separation confirmed by the time‐resolved spectroscopy. More importantly, the process of photo‐induced carrier transfer can be traced by in situ attenuated total reflection surface‐enhanced infrared tests, certifying that the effective electron transfer can promote N≡N dissociation and N 2 hydrogenation. As a result, InP QDs‐S 2− /MIL‐100(Fe) exhibits prominent performance with an outstanding NH 3 yield of 0.58 µmol cm −2 h −1 (3.09 times higher than that of MIL‐100(Fe)). This work reveals an important ultrafast dynamic mechanism for PEC NRR in QDs modified metal‐organic frameworks, providing a new guideline for the rational design of efficient MOFs photocathodes.