Abstract
Inorganic colloidal nanoparticles are known for their efficient catalytic reactivities, owing to their relatively small size and enhanced surface-to-volume ratio. Furthermore, the suitable selective incorporation of secondary metals can generate diverse bimetallic nanoparticles, further enhancing catalytic abilities through synergistic effects. Among synthesis approaches, peptide-based methods have demonstrated excellent ability in fabricating stable monometallic and bimetallic nanoparticles under facile and sustainable conditions. Furthermore, certain bio-synthesis approaches can achieve atom-level control over the morphologies and functionalities of nanoparticles. By utilizing the relatively weak and flexible non-covalent interactions between the peptide amino acids and the inorganic metal surfaces, the post-manipulation of peptide conformation on the metal surface becomes feasible. This could be accomplished through remote stimuli by incorporating a photoresponsive moiety, such as azobenzene, into the peptide sequence. This conformational alternation of the bio-capping ligands also provides a pathway for finely controlling nanoparticle catalysts. In this dissertation, to investigate control over nanoparticle morphologies, optical properties, and subsequent catalytic applications, the exploration of various surface capping ligands was employed in two parts. Initially, two Au@Pt Core@Shell nanocatalysts were fabricated using two Au-binding peptide sequences, AuBP2 and AgBP1, respectively. These stable bimetallic nanosystems confirm peptides’ fine-level control over morphology and subsequent enhanced catalytic hydrogenation ability across various substrates. Next, biohybrid photoswitchable capping ligands, peptide-azobenzene, were employed for the post-modulation of the inorganic surface. These demonstrate a new composition of photoswitchable peptide-capped Pt nanocatalyst system and the heterogeneous monolayer-capped Au nanoparticles.