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Bio-inspired approaches for materials synthesis and application are emerging as potentially sustainable approaches to achieve functional structures with selectively controlled properties (e.g., turn on catalysis). An attractive avenue to allow for selective functionality is optical stimulation; however, the ability to make nanomaterials light responsive for many applications remains challenging. One approach is to incorporate photoswitches into the surface adsorbed ligands which can stimulate a surface structural change that could have implications on the catalytic reactivity driven by the underlying metallic nanoparticle component. Herein were demonstrate the ability to drive optical switching of surface ligand overlayer structures on peptide-capped Pt nanoparticles. To this end, incorporation of an azobenzene unit into the surface-adsorbed peptide allows for the ability to optical reconfigure the ligand overlayer structure. This change results in direct manipulation of the catalytic properties of the Pt materials for olefin hydrogenation, which demonstrated changes in reactivity not only between different reagents, but also between the different ligand structures. Such results present information which could be used in the design of ligand interface structures to trigger specific reactivity control for a variety of reactions and materials for sustainable catalysis. 

The realization of multifunctional nanoparticle systems is essential to achieve highly efficient catalytic materials for specific applications; however, their production remains quite challenging. They are typically achieved through the incorporation of multiple inorganic components; however, incorporation of functionality could also be achieved at the organic ligand layer. In this work, we demonstrate the generation of multifunctional nanoparticle catalysts using peptide-based ligands for tandem catalytic functionality. To this end, chimeric peptides were designed that incorporated a Au binding sequence and a catalytic sequence which can drive ester hydrolysis. Using this chimera, Au nanoparticles were prepared, which sufficiently presented the catalytic domain of the peptide to drive tandem catalytic processes occurring at the peptide ligand layer and the Au nanoparticle surface. This work represents unique pathways to achieve multifunctionality from nanoparticle systems tuned by both the inorganic and bio/organic components, which could be highly important for applications beyond catalysis, including theranostics, sensing, and energy technologies. 

Bimetallic nanoparticles remain a promising avenue to achieve highly reactive catalysts. In this contribution, we demonstrate the use of a photoswitchable peptide for the production of PdAu bimetallic nanoparticles at a variety of Pd : Au ratios. Using this peptide, the biomolecular overlayer structure can be switched between two different conformations ( cis vs. trans ) via light irradiation, thus accessing two different surface structures. The composition and arrangement of the materials was fully characterized, including atomic-level analyses, after which the reactivity of the bimetallic materials was explored using the reduction of 4-nitrophenol as a model system. Using these materials, it was demonstrated that the reactivity was maximized for the particles prepared at a Pd : Au ratio of 1 : 3 and with the peptide in the cis conformation. Such results present routes to a new generation of catalysts that could be remotely activated for on/off reactivity as a function of the ligand overlayer conformation.