GaN nanowire as a reusable photoredox catalyst for radical coupling of carbonyl under blacklight-irradiation
Employing photo-energy to drive the desired chemical transformation has been a long pursuing subject. The development of homogeneous photoredox catalysts in radical coupling reactions has been truly phenomenal, however with apparent disadvantages such as the difficulty to separate catalyst and the often requirement of scarce noble metals. We therefore envisioned the use of hyper-stable III-V photosensitizing semiconductor with tunable Fermi level and energy band as the readily isolable and recyclable heterogeneous photoredox catalyst for radical coupling reactions. Using the carbonyl coupling reaction as a proof-of-concept, herein, we report a photo-Pinacol Coupling Reaction catalyzed by GaN nanowires under ambient light at room temperature with methanol as solvent and a sacrificial reagent. By simply tuning the dopant, the GaN nanowire shows significantly enhanced electronic properties. The catalyst showed excellent stability, reusability and functional tolerance. All reactions could be accomplished with a single piece of nanowire on Si-wafer.