(634e) Toward ‘One-Pot' Hard-Templating of Three-Dimensionally Ordered, Hierarchically Porous Carbon Films | AIChE

(634e) Toward ‘One-Pot' Hard-Templating of Three-Dimensionally Ordered, Hierarchically Porous Carbon Films

Authors 

Tian, Z. - Presenter, Lehigh University
Snyder, M., Lehigh University



Three-dimensionally ordered porous carbon thin films of tunable morphology, pore topology and hierarchy show promise in applications ranging among separation membranes, electrodes and catalytic supports. The current paradigm for realizing porous carbon films employs either ‘one-pot’ surfactant-based ‘soft’-templating or multi-step inorganic ‘hard’-templating.  While the so-called ‘hard’-templating approach provides promise over soft-templating approaches for more versatile accommodation of carbon sources (i.e., thereby tuning inherent material properties), tuning of pore structure and wall thickness, and bolstering film stability against uniaxial pore shrinkage, this method suffers generally from its characteristic multi-step nature.

Inspired by the simplicity of ‘one-pot’ soft-templating strategies, this talk will highlight progress toward realizing a facile ‘one-pot’ hard-templating method capable of deriving three-dimensionally ordered, hierarchically porous carbon films in order to exploit some of the benefits of hard-templating processes. Specifically, we will show how pre-formed size tunable silica nanoparticles (ca. 20-50 nm) can be co-assembled from aqueous solutions with a carbon source into conformal, thickness-tunable composite carbon-silica structures—a process akin to surfactant-directed approaches.  Carbonization, etching of the sacrificial silica template, and, in some cases, activation of the carbon results in ordered mesoporous-microporous carbon films of tunable thickness and pore size.  The process is robust to either direct deposition on surfaces with characteristic roughness of more than an order of magnitude larger than the template particle diameter as well as polymer-assisted transfer between various substrates (e.g., conductive glass, macroporous materials).

The ‘one-pot’, hard-templating process involves concentration-dependent adsorption of molecular carbon precursors onto the surface of the template silica nanoparticles prior to their assembly.  The sub-monolayer carbon precursor adsorption is manifested in modulated template particle assembly, pore wall thickness tunability, and even tailored graphene content, and thus electronic properties, of the final mesoporous carbon films.  This talk will highlight the mechanism of assembly, templating, pore windo tunability, and graphene domain formation through comprehensive analysis spanning HPLC adsorption studies, nitrogen and argon physisorption, XPS, cyclic voltammetry, and high-resolution electron microscopy.  The high surface area, apparently tunable graphene content (i.e. >50%), and facile and low-cost ‘one-pot’ synthesis of these ordered mesoporous carbon films on conductive substrates (i.e. FTO-glass) show promising applications as electrodes in both supercapacitor or dye-sensitized solar cell applications.