Optical Control of Biomimetic Nanoparticle Catalysts Based upon the Metal Component

Nanoparticle catalysts provide an intriguing route to achieving sustainable reactivity. Recent evidence has suggested that both the underlying metallic core and the passivating ligand layer can be exploited to control reactivity. The intimate interactions between the core metal and structure of the ligand layer can change based upon the metal used to generate the catalytic particle. Through judicious selection of both components, nanoparticle catalytic systems can be designed to be stimuli responsive for controlled reactivity. Herein, we demonstrate the effects of the underlying metal on the optically modulated catalytic activity of peptide-capped noble metal nanoparticles. For this, a photoswitch was incorporated into the peptide that enables reversible reconfiguration of the bioligand overlayer structure between two conformations based upon the isomerization state of the photoswitch. These changes in activity are dependent upon the inorganic metal of the particle core, and we exploit this dependence to demonstrate changes in the activity. The materials were fully characterized via spectroscopic methods and microscopy to correlate the observed reactivity to the material composition. The results provide new pathways to achieve remotely responsive catalysts that could be important for controlled multistep reactions or be exploited for other applications including biosensing and plasmonic devices

Converting Light Energy to Chemical Energy: A New Catalytic Approach for Sustainable Environmental Remediation

[Image: see text] We report a synthetic approach to form cubic Cu(2)O/Pd composite structures and demonstrate their use as photocatalytic materials for tandem catalysis. Pd nanoparticles were deposited onto Cu(2)O cubes, and their tandem catalytic reactivity was studied via the reductive dehalogenation of polychlorinated biphenyls. The Pd content of the materials was gradually increased to examine its influence on particle morphology and catalytic performance. Materials were prepared at different Pd amounts and demonstrated a range of tandem catalytic reactivity. H(2) was generated via photocatalytic proton reduction initiated by Cu(2)O, followed by Pd-catalyzed dehalogenation using in situ generated H(2). The results indicate that material morphology and composition and substrate steric effects play important roles in controlling the overall reaction rate. Additionally, analysis of the postreacted materials revealed that a small number of the cubes had become hollow during the photodechlorination reaction. Such findings offer important insights regarding photocatalytic active sites and mechanisms, providing a pathway toward converting light-based energy to chemical energy for sustainable catalytic reactions not typically driven via light