Fixation of Carbon Dioxide Using Molecular Reactions on Flexible Substrates

This chapter explores the possibilities of using flexible substrates as basis for carbon dioxide fixation or photocatalytic reduction. Flexible substrates facilitate the processing of the large active areas necessary for targeting the increased atmospheric content of carbon dioxide, and various coating methods and reactor designs from laboratory to industrial scale are presented; also the future challenges are discussed. In designing reactors, we describe how in situ infrared spectroscopy can be utilized as a simple analysis tool. A key challenge in these conversion systems is the necessary precautions that must be taken when evaluating the product outcome. Verifying actual conversion is most convincingly done by using isotopically labeled carbon dioxide, as several groups have found that using isotopically labeled CO2 leads to a product composition of species containing both 13C and 12C. This makes it likely that carbonates or other carbonaceous residues that reside on the chamber or catalyst surface somehow contribute to the products. The photochemistry of commonly used flexible substrate is reviewed, as the photochemical stability of these needs to be enhanced in order for this approach to be viable.