Facile preparation of functionalized and oxygen-deficient V2O5 nanosheets electrode as a versatile platform for biomimetic- and photoelectro-catalysis

Abstract

Facile preparation of functionalized and oxygen-deficient V 2 O 5 nanosheets modified electrode with enhanced biomimetic- and photoelectro-catalytic activity • One-step preparation of functionalized V 2 O 5 nanosheets electrode was demonstrated. • Roles of formamide in functionalizing V 2 O 5 nanosheets electrode was uncovered. • The obtained electrode (FTO|exf-V 2 O 5 ) can reduce Ag ions to Ag nanoparticles. • FTO|exf-V 2 O 5 shows remarkably high H 2 O 2 affinity and biomimetic activity. • Photoelectrocatalytic activity of FTO|exf-V 2 O 5 to methanol oxidation was explored. In this study, we present a facile and scalable preparation of formamide-functionalized and oxygen-deficient V 2 O 5 nanosheets (thickness: 30 ∼ 40 nm) modified electrode (FTO| exf -V 2 O 5 ) with promising peroxidase-like and photoelectrocatalytic activity. FTO| exf -V 2 O 5 was prepared by the direct top-down exfoliation of the V 2 O 5 sub-micron plates (thickness: 300 ∼ 550 nm) modified electrode (FTO| micro -V 2 O 5 ) in the presence of formamide as the exfoliation agent at mild conditions. Formamide molecules were found to adsorb on FTO| exf -V 2 O 5 and serve as the active sites for the reduction of noble metal, which not only enables the application of FTO| exf -V 2 O 5 for the recovery of noble metals but also allows further functionalization and electrocatalytic oxidation of H 2 O 2 . As compared with FTO| micro -V 2 O 5 , FTO| exf -V 2 O 5 had significantly higher oxygen vacancy (V O ) content and exhibited remarkably enhanced peroxidase activity with an ultra-low Michaelis-Menten constant of 68.24 μM and a high catalytic constant (or maximal turnover frequency) of 0.28 s −1 . Finally, FTO| exf -V 2 O 5 with lower dimension and higher V O content showed improved kinetics of charge-transport and interfacial charge-transfer, resulting in the enhanced activity towards photoelectrocatalytic oxidation of water and methanol. This work opens a new avenue for the preparation of exfoliated 2-D material based platform for biomimetic catalysis and energy conversion.