Gelatin biotemplated platinum aerogels

Abstract

Here gelatin biotemplated platinum aerogels were prepared from gelatin hydrogels equilibrated in K2PtCl4solutions ranging from 1-250 mM and reduced with sodium borohydride before supercritical drying in liquid CO2. Scanning electron microscopy revealed an average ligament diameter of 40.6 ± 9.7 nm and a pore size range of ∼10 – 200 nm. Thermogravimetric analysis correlated the ratio of metal content to biotemplate mass as a function of equilibrated platinum ion solution, and X-ray diffractometry indicated platinum metal with no detectable oxide phases. Electrochemical impedance spectroscopy indicated a specific capacitance of 1.92 F/g, with a corresponding specific electrochemical accessible surface area of 6.39 m2/g. Cyclic voltammetry performed in H2SO4demonstrated biotemplated platinum aerogel potential for catalytic and energy storage applications.

Noble Metal Composite Porous Silk Fibroin Aerogel Fibers

“…The structure of the nanofibrils and growth of the noble metal nanoparticles indicates the effects of reduction on the silk fibroin. It has been previously demonstrated that the reduction of these noble metals can be completed using gelatin and cellulose materials with higher reducing agent concentrations [4,5]. Figure 2 shows the SEM images of the silk fibroin aerogel with platinum and palladium after reduction with 100 mM sodium borohydride.…”

“…Due to the lower pH, gold metal ions are more attracted to the silk molecular structure caused by electrostatic interactions, which is visible as a higher density of decorated surface nanoparticles compared with the silk–platinum and silk–palladium aerogels (Figure S3). This has been discussed in other biopolymer-related work [4,5]. Silk fibroin has a repeating pattern of glycine, serine, and alanine forming polymer blocks with shorter block regions of non-repeating sequences [36].…”

“…Nevertheless, working with regenerated biopolymer solutions can enhance properties such as the tensile strength and porosity [3]. Furthermore, regenerated biopolymer solutions can be used as a structural network that can be combined with other materials to synthesize composites not found in nature [4,5]. Starting with biopolymers dissolved in polar solvents, such as water or alcohols, can be useful in providing varied biopolymer conformational folding to enhance the desired properties.…”

“…Furthermore, enhancing the properties of biopolymer gels, such as metallization for catalysis and sensing, can be achieved by equilibrating with gold, palladium, and platinum noble metal complexes, which, after electrochemical reduction, result in nanoparticle growth on the biopolymer nanofibrils [4,5]. Using silk fibroin as the material of choice to add conductive noble metal nanoparticles would enhance the versatility of this mechanically robust and biocompatible material.…”

Salt-Mediated Au-Cu Nanofoam and Au-Cu-Pd Porous Macrobeam Synthesis

“…Our group’s recent reports on direct reduction synthesis of noble metal aerogels [ 39 ] and salt-templated platinum macrobeams [ 40 ] suggest a possible route to achieving bi- and tri-metallic three-dimensional Au-Cu and Au-Cu-Pd nanostructures. The use of these synthesis methods in conjunction with biotemplating has also demonstrated the versatility of these approaches to yield porous noble metal structures [ 41 , 42 ].…”