CNT Microtubes with Entrapped Fe<sub>3</sub>O<sub>4</sub> Nanoparticles Remove Micropollutants through a Heterogeneous Electro‐Fenton Process at Neutral pH
Mojtaba Mohseni, Kristof Demeestere, Gijs Du Laing, Süleyman Yüce, Robert Keller, Matthias Weßling
Abstract
Abstract Catalyst‐coated carbon electrodes require two preparation stages: electrode assembly using carbon and polymeric binders and subsequent catalyst immobilization on the porous carbons electrode. Such conventional coating methods require several steps, which is time‐, chemical‐, and energy‐consuming. Also, polymeric binders can impair the porosity and block catalytic sites of final electrodes. This study introduces a novel one‐pot synthesis method in which Fe 3 O 4 nanoparticles are entrapped within a multi‐walled carbon nanotube network, the latter being templated with microtubular geometry. Such carbon microtubes (CMT) represent a standalone geometry, serving as a binder‐free electrode for an energy‐efficient heterogeneous electro‐Fenton (HEF) process. Fe 3 O 4 ‐containing CMTs remove carbamazepine (CBZ), a frequently detected pharmaceutical micropollutant in water bodies. While almost all literature reports degradation at acidic conditions requiring the use of acid, this material system functions at pH 7 ± 0.3 with lengthy reusability. The remarkable mineralization of the total oxidized CBZ emerges from the confinement of oxidation by‐products in CMTs’ 3D framework, where unselective radicals are formed once the electro‐generated H 2 O 2 reacts with embedded Fe 3 O 4 . Additionally, the 3D network prevents the entrapped catalysts from leaching in acidic environments because of the increased local pH during electrolysis.