Electronic Metal-Support Interactions for Electrochemiluminescence Signal Amplification

Au nanoparticle-amplified electrochemiluminescence (ECL) signals are generally realized by nanoparticle morphology modification, functionalization, and nanoalloys formation. It remains a great challenge to utilize the intrinsic catalytic activity of spherical Au nanoparticles for ECL performance improvement. In this work, we prepared the oxygen vacancy-rich CoAl-layered double hydroxide (LDH-O_v)-supported spherical Au nanoparticles via alkali etching of LDH and electrodeposition of Au nanoparticles on the surface of LDH. It was found that the luminol ECL signals of the as-prepared system were significantly enhanced by forming the strong electronic metal-support interaction (EMSI) between Au nanoparticles and LDH-O_v. The further mechanism study demonstrated that EMSI can increase the electron density of interfacial Au atom (Au^δ-) due to a redistribution of charge and promote electron transfer between Au species and LDH-O_v. This study not only introduces EMSI to the ECL field but also paves a new way to the applications of the intrinsic activity of spherical Au nanoparticles in ECL signal amplification. We anticipate that EMSI would be applied to other metal nanocatalysts for the development of highly efficient ECL systems.