Effects of the Material Structure on the Catalytic Activity of Peptide-Templated Pd Nanomaterials

Bioinspired approaches represent emerging methods for the fabrication and application of nanomaterials under desirable ambient conditions. By adapting biomimetic processes to technological applications such as catalysis, new directions could be achieved for materials that are reactive under energy efficient and ecologically friendly conditions. Such materials have been prepared using a self-assembling peptide template in which non-spherical Pd nanostructures can be generated. Based upon the Pd/peptide ratio, different inorganic morphologies can be prepared within the peptide scaffolds, including nanoparticles, linear nanoribbons, and complex nanoparticle networks (NPNs). These materials are catalytically reactive; however, the effects of the template and Pd morphology remain poorly understood. To ascertain these effects, we present an in depth catalytic analysis of the bioinspired peptide. based system using two vastly different reactions: Stile C C coupling and 4-nitrophenol reduction. For all of the systems studied, enhanced reactivity was observed for the Pd nanoparticles and NPNs over the nanoribbons. This effect is suggested to arise from two key structural characteristics of the materials: the amount of inorganic surface area and the penetration depth within the peptide scaffold. Such results are important for the design and development of selective nanocatalytic systems, where the composite structure works in conjunction to mediate the overall activity.