An Amine-Functionalized Titanium Metal–Organic Framework Photocatalyst with Visible-Light-Induced Activity for CO₂ Reduction

Home > News > An Amine-Functionalized Titanium Metal–Organic Framework Photocatalyst with Visible-Light-Induced Activity for CO₂ Reduction

Summary:
The authors from Fuzhou University developed an amine-functionalized titanium MOF, NH₂-MIL-125(Ti), featuring visible-light absorption up to 550 nm and high CO₂ affinity, achieving 8.14 μmol formate production in 10 h under visible-light-driven CO₂ reduction.

Background:
1. To address UV-only activity and low efficiency of traditional TiO₂-based CO₂ photocatalysts, previous researchers explored Ti-zeolites or doped TiO₂, yet visible-light response and product yields remained limited.
2. The authors proposed ligand engineering of MIL-125(Ti) by substituting H₂BDC with 2-aminoterephthalic acid, obtaining NH₂-MIL-125(Ti) that harvests visible light and boosts CO₂ adsorption.

Research Content:
1. Synthesis: Solvothermal reaction of Ti(OC₄H₉)₄ with 2-aminoterephthalic acid in DMF/MeOH at 150 °C for 72 h, followed by methanol exchange and evacuation at 200 °C.
2. Characterizations:
   1) BET – 1302 m² g⁻¹ (Langmuir 1719 m² g⁻¹); microporous structure retained.
   2) SEM/TEM – octahedral crystals ~500 nm.
   3) UV–vis DRS – absorption edge extends to 550 nm; DRIFTS confirms free –NH₂; XPS & ESR verify Ti³⁺ formation under light; Mott–Schottky indicates suitable CB for CO₂ reduction.
3. Application: 50 mg catalyst, MeCN/TEOA (5:1), 420–800 nm Xe lamp; 8.14 μmol HCOO⁻ in 10 h, stable for at least four cycles; no activity with MIL-125(Ti) or N-doped TiO₂ under >450 nm.
4. Mechanism: LMCT excitation → ligand-to-Ti electron transfer generates Ti³⁺; Ti³⁺ transfers electron to adsorbed CO₂ forming HCOO⁻ while TEOA donates holes; reversible photochromic yellow-green-yellow cycle evidences Ti³⁺/Ti⁴⁺ redox shuttle.

Outlook:
This study pioneers visible-light CO₂ reduction over an amine-functionalized MOF, proving ligand modification as a facile route to solar-active CO₂ photocatalysts and opening avenues for recyclable amine-donor coupled systems.

An Amine-Functionalized Titanium Metal–Organic Framework Photocatalyst with Visible-Light-Induced Activity for CO₂ Reduction
Authors: Yanghe Fu, Dengrong Sun, Yongjuan Chen, Renkun Huang, Zhengxin Ding, Xianzhi Fu, Zhaohui Li
DOI: 10.1002/anie.201108357
Link: https://doi.org/10.1002/anie.201108357

The above review is for academic progress sharing. For any errors or copyright issues, please contact us for correction or removal.