Construction of H2O2-responsive asymmetric 2D nanofluidic channels with graphene and peroxidase-mimetic V2O5 nanowires.

The flexible two-dimensional (2D) nanosheet structure, high specific surface, and unique electrical properties make graphene an emerging nano-building block for molecule-responsive nanochannels. Herein, we report a novel graphene and V2O5 nanowire-based porous asymmetric membrane, which shows excellent catalytic performance and sensitive and quick response for H2O2. Poly(diallyldimethylammonium chloride)-functionalized graphene nanosheets were made into restacked lamellar film with porous structure and high anion selectivity. V2O5 nanowire, a kind of enzyme-mimetic nanomaterial, was mounted on one side of the graphene membrane through a sequential vacuum filtration method. The V2O5 nanowires on the membrane have high catalytic activities for H2O2 reduction, with the Michealis-Menten constant (KM) of 1.74 mM, better than various reported peroxidase-based nanocomposites and peroxidase mimics. This composite membrane showed quick response to H2O2 within 5 s, with good reproducibility and high operational stability. The responsive linear range was from 10 μM to 1 mM, with the detection limit of 9.5 μM. This fabrication of 2D layered nanomaterials and enzyme mimics could be extended for developing novel smart molecule-responsive devices. Graphical abstract ᅟ.