Synthesis of Porous Copper Nanowires Aerogels on CNT-DNA Substrates

Biological hydrogels can serve as 3-dimensional bio-templates for tunable nano-porous materials that serve as both electrochemically active high surface area and structural material. We present a general approach to 1) form a composite biopolymer-carbon nanotube hydrogel using covalently crosslinked DNA-CNT, 2) equilibrate the hydrogel bio-template using Na₂PdCl₄ solution to mediate direct metal deposition, and 3) utilize an electroless copper deposition solution to form a porous copper nanowire array on the DNA-CNT substrate. Nanostructure is dependent on the biotemplate molecule, crosslinking mechanism, and drying method. Such multi-functional electro-mechanical materials are envisioned to enable a broad range of applications such as sensors, photovoltaics, catalytic systems, fuel cells, and energy absorption. This work allowed for the synthesis of metal aerogels and biotemplated metal aerogels using a method where the gel was cast directly into a centrifuge tube. The cast samples were then processed using three solutions to prepare and deposit metal directly onto the DNA-CNT substrate forming a biotemplated copper nanowire array. Nanostructured porous metals offer a wide range of applications including catalysis, energy storage and conversion, and sensing. The formation of free-standing metal aerogels with high specific surface area and hierarchical porosity confers significant advantages for conductivity, mass transfer properties, reaction specificity, and strength. This has previously been achieved with a direct reduction method,¹ as well as on gelatin,² and cellulose nanofiber templates.³ To further demonstrate multi-functional nanostructured electrodes, hierarchical DNA-CNT nano-composite aerogels will continue to be explored.

KEYWORDS: porous, carbon nanotubes, copper

[1] F. John Burpo*, Enoch A. Nagelli, Lauren A. Morris, Joshua P. McClure, Madeline Y. Ryu, Jesse L. Palmer. “Direct Solution-Based Reduction Synthesis of Au, Pd, and Pt Aerogels.” J. Mat. Res. 2017, 32 (22), 4153-4165.

[2] F. John Burpo*, Alexander N. Mitropoulos, Enoch A. Nagelli, Madeline Y. Ryu, Jesse L. Palmer. “Gelatin Biotemplated Pt Aerogels.” MRS Advances, 2018, 3(47-48), 2875-2880.

[3] F. John Burpo*, Alexander N. Mitropoulos, Enoch A. Nagelli, Lauren A. Morris, Joshua P. McClure, Jesse L. Palmer, Madeline Y. Ryu. “Cellulose Nanofiber Biotemplated Palladium Aerogels.” Molecules. 2018, 23, 1405-1418.