High performance stability of titania decorated carbon for desalination with capacitive deionization in oxygenated water

Abstract

Performance stability in capacitive deionization (CDI) is particularly challenging in systems with a high amount of dissolved oxygen due to rapid oxidation of the carbon anode and peroxide formation. For example, carbon electrodes show a fast performance decay, leading to just 15% of the initial performance after 50 CDI cycles in oxygenated saline solution (5 mM NaCl). We present a novel strategy to overcome this severe limitation by employing nanocarbon particles hybridized with sol–gel-derived titania. In our proof-of-concept study, we demonstrate very stable performance in low molar saline electrolyte (5 mM NaCl) with saturated oxygen for the carbon/metal oxide hybrid (90% of the initial salt adsorption capacity after 100 cycles). The electrochemical analysis using a rotating disk electrode (RDE) confirms the oxygen reduction reaction (ORR) catalytic effect of FW200/TiO₂, preventing local peroxide formation by locally modifying the oxygen reduction reaction.