Interfacial Cu2O enables the unanticipated boosting activity of arc-converted graphitic chain mail encapsulated Cu nanocatalysts

Encapsulation of Cu nanoparticles by carbon chain mail is a promising approach to extend the service endurance. However, the diffusion of oxygen across the surfaces and interfaces of Cu nanoparticles (NPs) may induce obvious changes to their surface compositions, thereby dramatically altering catalytic properties. Here we reported an unanticipated boosting catalytic activity of graphitic chain mail-encapsulated Cu nanocatalysts (1.3- to 6.8-fold enhancement from initial 1.6–13.4 s−1g−1 to stable 6.6–21.5 s−1g−1) for the reduction of 4-nitrophenol by simply immersing these NPs in water for 10 days without any further treatment. The graphitic shells were arc-converted from sixteen types of biomass residuals and polymeric wastes. The rising catalytic activity was attributed to the temporal formation of Cu2O at the interface of Cu core and graphite shell, which was derived from the diffusion of dissolved oxygen across the defective graphitic chain mail. The increment of catalytic activity was linearly related with the rising content of Cu2O. The monotonous relations of initial and enhanced activities with shell thickness and interfacial composition of NPs were also well established. This work provides a new insight into the interfacial manipulation of core/shell nanocatalysts, and paves a versatile path for the high value-added utilization of carbon wastes.