Botanically templated macroporous materials and their energy catalysis applications

Developing catalytically active materials with structured forms and higher surface areas is useful to increase their activity in many different catalytic processes for energy and fuel production. This thesis describes the use of common plant leaf structures as templates to make complex porous materials several applications. The plant materials are prepared using chemical dehydration that removes water but leaves the larger structure of the plant leaf intact as a foam-like material. The dehydrated plant materials can absorb various precursors to form a variety of earth abundant metal based materials upon heating to 500 °C or higher.

Some metal oxides such as zinc oxide and titanium dioxide are useful for harnessing light energy to break down organic molecules or generate fuels like hydrogen and oxygen from water. Making these materials as porous structures may improve their catalytic activity. Other oxides like nickel and cobalt oxide are useful for the generation of oxygen gas from water using electrical energy. The catalysts for hydrogen and oxygen production are important for the development of fuel cell technologies for green energy.

Porous carbons are a popular material for adsorbing pollutants and ions from water as well as serving as supports for metals like platinum in electrochemical applications. The dehydrated plant materials can be carbonized into high surface area carbon structures that can be decorated with metal particles covering the surface. These surface particles can then be converted into other materials like metal sulfides, which are useful in the production of hydrogen gas from water.