| Popis: |
Electrochemical decarboxylation of acetic acid on boron-doped diamond electrodes (BDD) was studied as a possible means to decrease the acidity of pyrolysis oil. It is shown that decarboxylation occurs without competitive OER on BBD electrodes to form methanol and methyl acetate by consecutive reaction of hydroxyl radicals with acetic acid. The performance is little affected by the applied current density (and associated potential), concentration, and the pH of the solution. At current densities above 50 mA/cm2, FEs of 90% towards decarboxylation products are obtained, confirmed by situ electrochemical mass spectrometry (ECMS) investigation showing only small amounts of oxygen formed by water oxidation. Using platinum-modified BDD electrodes, it is shown that ethane-selectivity, the Kolbe product, strongly depends on the shape and geometry of the platinum particles. Using nano-thorn alike Pt particles, a faradaic efficiency of approx. 40 % towards ethane can be obtained, whereas 3D porous platinum nanoparticles showed high selectivity towards OER. Using thin platinum layers, a high FE towards ethane was obtained >70%, which is thickness-independent at layer thicknesses above 20 nm. Comparison with other substrates revealed that BDD is an ideal support for Pt functionalisation giving advantage of stability, high valuable products formation (ethane and methanol). In short, this work provides guidelines for electrode fabrication in the context of the electrochemical upgrading of biomass feedstocks by acid decarboxylation. |
