Self-activated Au4Ni2 system with electronic antenna: Boosting photocatalytic oxidative coupling of amines and mechanistic insight

Efficient and selective oxidative coupling of amines by Photocatalytic is highly desirable for scientific and industrial fields. A thorough understanding of photocatalytic mechanisms is a necessary condition for realizing the development of novel photocatalysts . Herein, we design a novel Au 4 Ni 2 (SR) 8 with precise atomic structure for oxidative coupling of amines with TOF values up to 1666.7 h −1 . Based on systematic characterization and theoretical simulations, we elaborated that the Ni-S site in Au 4 Ni 2 (SR) 8 system as an electron antenna to accelerate the attraction light carriers to the nanocluster (NC) surface for single electron transfer (SET) with amines. Meanwhile, a series of intermediates such as Au 4 Ni 2 (SR) 8 +PhCH 2 NH 2 , PhCH=NH and PhCH(NH 2 )NHCH 2 Ph intermediates were successfully captured by paper spray mass spectrometry (PS-MS). Compared with Ag 4 Ni 2 (SR) 8 , Au 4 Pd 2 (SR) 8 and Ag 4 Pd 2 (SR) 8 , Au 4 Ni 2 (SR) 8 can significantly reduce the energy barrier of electron transfer during photocatalysis . In particular, the O 2 here is specifically activated to O 2 • – by stimulating amine C 6 H 5 CH 2 NH 2 •+ under the action of Au 4 Ni 2 (SR) 8 , avoiding the generation of multi-component reactive oxygen species (ROS). This study provides an avenue to construct photocatalysts with high photo response to boost the solar-energy conversion. • The Au 4 Ni 2 (SR) 8 system specifically activate O 2 to form a single ROS (O 2 .- ). • The Au 4 Ni 2 (SR) 8 system exhibit excellent performance for amines oxidative coupling. • The combination of the electronic antenna Ni-S site and Au element promotes the reaction. • The intermediates in the catalytic cycle were verified by experiments and DFT. • The Au 4 Ni 2 (SR) 8 system truly visualizes the catalytic process at the molecular level.