Precise gradient separation of nanoparticles using reduced graphene oxide-polyoxomolybdate membranes

The purification and size sieving of nanoparticles (NPs) represents a significant scientific challenge. Herein, the rGO-polyoxometalates (POMs = PMo, Mo and Mo) membranes were fabricated successfully via a simple and scalable POMs-assisted in-situ photoreduction strategy. When the mass ratio of rGO to PMo was 1:30, the resultant rGO-PMo membranes with highly ordered and uniform nanochannels of 1.0 nm can be obtained, which showed an accurate carbon quantum dots (CQDs) separation with a cut-off size approximately 1.0 nm. Further increase of the size of the interlayered POMs from PMo (1.0 nm), {Mo} (2.9 nm) to {Mo} (3.8 nm), the resultant rGO-PMo, rGO-Mo and rGO-Mo exhibited precise gradient separation of CQDs and Au nanoparticles by size exclusion effect. The results pave a promising way to construct new two-dimensional (2D) membranes for highly efficient size-selective separation. (Figure presented.)