Achieving Highly Electrocatalytic Performance by Constructing Holey Reduced Graphene Oxide Hollow Nanospheres Sandwiched by Interior and Exterior Platinum Nanoparticles

Two-dimensional (2D) graphene nanosheets are considered as an attractive support to load metal nanoparticles for applications in fuel cells due to their extraordinary physicochemical properties arising from the 2D nanostructure. However, fabricating graphene/metal nanoparticle nanohybrids with superior electrochemical performance remains a great challenge to date. In this work, we, for the first time, demonstrate a novel and ingenious approach to fabricate holey reduced graphene oxide hollow nanospheres sandwiched by interior and exterior Pt nanoparticles (denoted as Pt@holey r-GO@Pt hollow nanospheres), using uniform SiO2 nanospheres as the templates. The Pt@holey r-GO@Pt hollow nanospheres represent a new type of metal/graphene heteroarchitecture due to their rich porosity, abundant active sites, facilitated reaction kinetics, and outstanding structural stability. Thanks to these distinguished merits, the as-prepared Pt@holey r-GO@Pt hollow nanospheres exhibit greatly enhanced electrocatalytic performances toward the oxygen reduction reaction and methanol oxidation reaction as compared with the intact counterparts and commercial Pt/C catalyst, showing great potential in fuel cell devices. The smart strategy outlined here should be readily applicable to rational design of other graphene/metal nanoparticle nanohybrids for energy storage and conversion applications in the future.