Using Pt/CNT or Fe/CNT electrocatalysts it is possible to convert carbon dioxide to liquid fuels, particularly isopropanol. Fe/CNT shows a better behavior than Pt/CNT, although a faster deactivation. The main reason of deactivation is cross-over of the electrolyte, particularly of K ions. They react with iron particles and cause their dissolution and migration. In the case of Pt/CNT there is no, or minor, dissolution of metal, but potassium covers the Pt particles and/or induce deactivation. It is shown, however, that the electrolyte was necessary to simulate the half-cell of the full photoelectrocatalytic device, while in the latter no electrolyte is needed, being the protons and electrons produced by water splitting. The elimination of the electrolyte probably could eliminate or significantly reduce a main cause determining the observed fast deactivation

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Homogeneous (Cu 2+ ions) and heterogeneous (Cu 2+ -pillared clay) Fenton-like catalysts have been compared in the conversion of p-coumaric acid. The performances of the two classes of catalysts are similar for an analogous amount of copper, but there are some relevant differences in terms of (i) the presence of an induction time, (ii) the turnover frequency, (iii) the efficiency in the use of H 2 O 2 , (iv) the initial attack of p-coumaric acid (hydroxylation on the aromatic ring or oxidative attack on the double bond of the lateral chain), and (v) the effect of dissolved oxygen on the removal of total organic carbon (TOC). These differences were interpreted in terms of reaction network of generation of radical oxygen species and of organics conversion. The possible formation of a surface peroxo adduct coordinated to a copper binulcear site was also evidenced for the solid heterogeneous catalyst.

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