Tailoring the Stability, Photocatalysis and Photoluminescence Properties of Au11 Nanocluster via Doping Engineering
Dopants in the gold nanoclusters have been proved to definitely mediate the intrinsic electronic property of the homo-clusters. In this work, we report the precise synthesis of atomically precise Au8Ag3(PPh3)7Cl3 alloy nanoclusters with multiple Ag dopants for the first time. Its structure is resolved by single crystal X-ray crystallographic analysis. The Au8Ag3(PPh3)7Cl3 possesses a similar structure topology with the well-known Au11(PPh3)7Cl3 nanoclusters. It is observed that the three Ag atoms are fixed at the cluster’s surface and selectively bind with the three chlorine ligands in a C3 axis manner. And the alloy nanoclusters exhibit a close shell electronic structure (i.e., 8(Au 6s1) + 3(Ag 5s1) – 3(Cl) = 8e), evidenced by the electrospray ionization mass spectrometry (ESI-MS). The photothermodynamic stability alloy clusters remarkably improved, e.g. full decomposition after seven days under the sunlight irradiation vs. three days for Au11(PPh3)7Cl3. DFT calculation indicates the Ag dopants in the C3 axis manner can obviously delocalize the electrons of Au to the orbital of P atoms and then mediate the electronic property of the clusters. The shrink of HOMO-LUMO gap to 1.67 eV of Au8Ag3(PPh3)7Cl3 is also observed as compared with homo-nanocluster Au11(PPh3)7Cl3 of 2.06 eV. The electrochemical gap of Au8Ag3(PPh3)7Cl3 alloy nanocluster is 1.272 V which is higher than the Au11(PPh3)7Cl3 that indicates higher electrochemical stability evidenced by differential pulse voltammetry (DPV) method. The Au8Ag3(PPh3)7Cl3 exhibits specific three PL peaks at 405, 434 and 454 nm. Finally, the AuAg alloy clusters exhibit two time activity of the homo gold clusters in the photooxidation of benzylamine, which is mainly due to the unique electronic properties of the alloy clusters. The controllable heteroatom doping engineering is a powerful method to definitely tune the clusters’ electronic properties and then improve their photothermodynamic and electrochemical stability simultaneously for potential photocatalytic performances.