Graphene Quantum Dots Drive Spontaneous Metal Reduction to form Stable and Electroactive Core‐Shell Nanocolloids

Abstract

This work demonstrates a spontaneous synthesis of ∼8.0, ∼7.0, and ∼3.0 nm diameter Au, Ag, and Pt cores; respectively, wrapped by as-synthesized crystalline graphene-quantum dots(GQDs). Functional sp2- and sp3-hybridized carbons play a crucial role upon the synthesis, electronic distribution at the interface, and conductive sites for improving the electrocatalytic response. Au nanohybrids (NHs) demonstrated two-fold increase in current density with respect to conventional citrate-coated Au nanoparticles. This was attributed to conductive sp2- hybridized carbons and the gain of charge density at the surface of Au as demonstrated by DFT calculations. Due to the sp3-carbons at the shell, these NHs also behave like simple chemical compounds because they can be precipitated, stored for long periods of time, and redispersed without apparent changes in their properties. The resultant nanocolloids exhibit exceptional stability under harshconditions. These attributes make them useful NHs with great potential for broad applications.