Interplay between remote single-atom active sites triggers speedy catalytic oxidation

Understanding interaction between active sites in heterogeneous catalysis is a grand challenge owing to difficulty in extracting information from different active sites. We report a solution to this problem by showing that electron conduction can facilitate direct interplay of distant active sites. By fabricating two single-atom site catalysts (manganese dioxide-encapsulated metallic silver atomic wires) with one or two ending silver atoms of each wire exposed on surfaces, we find that only the catalyst with both ending silver atoms exposed can trigger low-temperature carbon monoxide oxidation, which provides unequivocal evidence that interaction between active sites is possible upon eligible electron conducting. This result indicates that the interaction between active sites might be universally present in catalysis reactions when there is effective communication between the active sites

Stable single atomic silver wires assembling into a circuitry-connectable nanoarray

Atomic metal wires have great promise for practical applications in devices due to their unique electronic properties. Unfortunately, such atomic wires are extremely unstable. Here we fabricate stable atomic silver wires (ASWs) with appreciably unoccupied states inside the parallel tunnels of α-MnO2 nanorods. These unoccupied Ag 4d orbitals strengthen the Ag–Ag bonds, greatly enhancing the stability of ASWs while the presence of delocalized 5s electrons makes the ASWs conducting. These stable ASWs form a coherently oriented three-dimensional wire array of over 10 nm in width and up to 1 μm in length allowing us to connect it to nano-electrodes. Current-voltage characteristics of ASWs show a temperature-dependent insulator-to-metal transition, suggesting that the atomic wires could be used as thermal electrical devices.</p