Dendron-functionalized multiwalled carbon nanotubes incorporating polyoxometalates for water-splitting catalysis*

Carbon nanotubes (CNTs) are versatile nanomaterials with applications spanning from medicinal chemistry and biology, to electronics as field effect transistors or energy as fuel cells. The major drawback stems from the CNT insolubility in most of the organic and aqueous media, which severely hampers the material processability. To overcome this problem, functionalization of CNTs is generally accomplished by either covalent strategies resulting in the modification of the CNT backbone via radical reactions, fluorination, and/or cycloaddition reactions, or noncovalent protocols, exploiting multiple weak interactions (hydrophobic, van der Waals, electrostatic) with suitable reagents. Herein, we highlight that a rewarding approach includes a combination of covalent/noncovalent methods, by a tailored synthetic modification of the CNT surface with polycationic dendrimeric chains, fostering the successive decoration with a multimetallic and polyanionic water oxidation catalyst. The outcome is a hybrid nanomaterial with unperturbed CNT electrical properties, in close contact with a unique multi-electron catalyst enabling electrocatalytic water splitting with high efficiency at low overpotentials.