New insights into nanostructure/functionality-dependent catalysis of pollutants by arc-designing graphite-encapsulated silver nanoparticles

Abstract

Encapsulation of plasmonic nanoparticles in nanoshells is a promising strategy to overcome their oxidation-coalescence in the heterogeneous catalysis process. Tailoring of nanostructure/functionality to enable the efficient synergistic integration of core and shell is highly desired to enhance the plasmonic catalysis. This study applied a one-step arc discharge to design graphite-encapsulated silver (Ag@G) catalysts with tunable morphologies (14.3–46.9 nm of cores, 1.38–3.43 nm of shells) and surface functionalities (hydrophobization, or amination with maximum 2.70 × 1017/mg of Ag@G). Highly nanostructure/functionality-dependent catalysis of aquatic pollutants was established. Specifically, tailoring defective shells with thinner thickness enabled the efficient synergism of strong π-π coordination of 4-nitrophenol and effective electron transfer of donors. Aminated Ag@G with ultrathin shells presented an optimal reduction for Cr(VI), establishing a negative relation of thickness with formic acid-induced reduction. Amino with proper densities (9.6–20.9/nm2) induced the capture of Cr(VI) ultrafast. Moreover, reductive N heteroatoms with proper densities (e.g., 27.7 of N/nm2) provided abundant lone pair electrons without the dramatic decline of conductivity, ensuring a favorable reduction of Cr(VI). Since arc discharge was versatile for the industrial production of nanomaterials, our work would trigger a new upsurge to arc-design nanostructures/functionalities for the catalysis and decontamination.