posted on 2021-11-24, 00:43authored byDániel Zámbó, Pascal Rusch, Franziska Lübkemann, Nadja C. Bigall
Noble-metal-based
electrocatalysts usually contain small nanoparticle
building blocks to ensure a high specific surface area as the scene
for the surface processes. Here, we show that relatively large noble-metal
nanorods are also promising candidates to build up functional macrostructures
with prominent electrocatalytic activity. After optimizing and upscaling
the syntheses of gold nanorods and gold bipyramid-templated silver
nanorods, cryoaerogels are fabricated on a conductive substrate via flash freezing and subsequent freeze drying. The versatile
cryoaerogelation technique allows the formation of macrostructures
with dendritic, open-pore structure facilitating the increase of the
accessible nanorod surfaces. It is demonstrated via electrochemical oxidation and stripping test experiments that noble-metal
surface sites are electrochemically active in redox reactions. Furthermore,
gold nanorod cryoaerogels offer a platform for redox sensing, ethanol
oxidation reaction, as well as glucose sensing. Compared to their
simply drop-cast and dried counterparts, the noble-metal nanorod cryoaerogels
offer enhanced activity due to the open porosity of the fabricated
nanostructure while maintaining structural stability.