SCIENTIFIC REPORT CO2CHEM - Sviluppo di un sistema elettrochimico di co-elettrolisi di CO2 ed H2O ad elettrolita polimerico operante a bassa temperatura per la riduzione di CO2 - 3rd Report (R.E. 11/17)

The research activities carried out in the final period of the CO2-chem contract regarded the investigation of electrolysis cells based on anionic membranes and non-noble metals catalysts for the production of alcohols. The electroreduction of CO2 or carbonate-based solutions (i.e. CaCO3 and Na2CO3) fed to the cathode was studied. The possibility to feed directly carbonate solutions or CO2 together with the recirculation of carbonate may represent a significant advantage for these electrochemical devices because of the large availability of calcareous stones which represent a concentrated source for increasing CO2 solubility. When this concept was started to be investigated at CNR-ITAE, the use carbonate solution as recirculation feed for this device represented a progress beyond the state-of-the-art of co-electrolysis devices. In the last year some similar concepts have appeared in the literature. Tests with carbonate solutions were carried out already in the second period, in particular for the cell named as "cell 7". The tests carried out in the final period allowed to characterize the difference in behaviour between CO2 and carbonate solutions feed to the cathode with carbonate feed recirculated at the anode in both cases. Then, new cells based on different materials and experimental conditions (compared to these already studied in the previous period) were investigated in order to assess the best operation conditions for this device. Two different cathodes were studied corresponding to NiCu and Cu as catalytic phase dispersed on C in order to improve the electronic percolation inside the electrocatalysts. Such materials were synthesised by using a CNR-ITAE procedure referred to "oxalate method" [1]. Then, in order to improve the ionic percolation within the catalytic layer an ink was prepared with the addition of the PFSA ionomer. Whereas, the novel operation conditions were referred to the cell temperatures, humidification, cell potentials and concentrations of salt solutions.