Pd/Ag and Pd/Au bimetallic nanocatalysts on mesoporous silica for plasmon-mediated enhanced catalytic activity under visible light irradiation

A systematic comparison of plasmonic properties and catalytic performances has been performed with Pd deposited bimetallic nanostructures of plasmonic Ag and Au. Mesoporous silica (SBA-15) supported Ag and Au nanoparticles (NPs) were synthesized using a microwave assisted alcohol reduction system. 1-Hexanol and ethylene glycol were employed as reducing agents for Ag and Au precursors, respectively, depending on their reduction ability to obtain metallic NPs. Further decoration with Pd NPs was achieved via localized surface plasmon resonance (LSPR)-assisted deposition under visible light irradiation. The formation of bimetallic NPs was confirmed by various characterization techniques, such as UV-vis spectroscopy, EXAFS, TEM, EDX and XPS. The obtained Pd/Au and Pd/Ag NPs exhibited specific photocatalytic activity in the Suzuki coupling reaction and hydrogen production from ammonia borane (AB), respectively. Moreover, we have explored the possible tunability of the plasmonic catalysts owing to change in the surrounding environment and electron injection.