This poster presentation with detail our recent efforts using sensitive living botanical structures as interconnected and complex physical templates for inorganic oxide and porous carbon growth. We have developed a room-temperature single-step chemical dehydration route to leaf structures that parallels processes like supercritical drying methods or sequential multi-step alcohol soak processes and leads to near complete removal of volatile and mobile components of plant leaves (~90% weight loss). The resulting carbon and oxygen rich lignin/cellulose leaf structures contain wide open vascular and cellular networks that readily accept solution infiltration deep into the core of the leaf from a range of metal precursors, including neat liquid sol-gel precursors such as Ti(i-OPr)4, and metal halides or acetates dissolved in methanol or other polar solvents. In the case of 3d metal salt infiltration, subsequent heating of the soaked template in air at ~500-800 °C produces porous metal oxides such as Co3O4 and NiO and solid-solutions result from mixed metal infiltration. When post-infiltration heating is conducted under inert atmosphere, nanoscale reduced metals such as Ni or Co are found to decorate a porous conducting carbon reminiscent of the original leaf. The synthesis and characterization of several 3d metal porous oxide and carbon structures and their use in electrocatalytic and photocatalytic redox reactions will be described. Several structures with Co and Ni show utility in electrochemical oxygen evolution reactions (OER) at potentials comparable to those found from nanoparticle materials. The identification and potential impact of naturally occurring residual plant minerals such as calcium in the final isolated products will also be presented.

Synthesis and catalytic reactions with macroporous botanically templated metal oxides and metal on carbon structures

253rd National Meeting (2017)

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