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A simple one-pot approach to the in situ construction of ultrathin shells is developed to create a new highly efficient and durable Pt-based electrocatalyst for the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). Herein, the synthesized ultrathin PdPtAg-shells are located on twinned PdAg nanocrystals and deposited onto graphene (G) (denoted by PdAg@PdPtAg/rGO). The PdAg@PdPtAg/rGO nanocrystal shows a low overpotential of 22 mV at 10 mA cm−2 and excellent electrochemical stability with 99.5% retention over either 12 h or 30 000 cycles of HER. Meanwhile, its ORR activities in acidic and alkaline media are very high and better than that of commercially available Pt/C. Both the experimental and calculated results suggest that the presence of an ultrathin PdPtAg alloy shell synthesized on a PdAg twinned support is the main reason for the greatly enhanced activities. Moreover, the twinned PdAg nanocrystal provides a number of twinned grain boundaries and defect sites (such as step, edge and kink sites). This typical structure represents a new strategy for synthesizing high-performance Pt-based catalysts, promoting their practical applications in energy conversion and storage devices.

The influence of plasma pretreatment on the catalytic performance of Zn based catalyst in acetylene hydration was studied. Furthermore, the atmosphere (N2, O2, NH3, air) and process conditions (pretreatment time, pretreatment power, gas flow) of plasma pretreatment were investigated systematically. The activity results showed that both the conversion and selectivity of the P-Zn/MCM-41 catalyst treated by oxygen plasma improved significantly. The characterization results suggested that the plasma treated catalyst enhances the mutual effect between the Zn species and MCM-41 carrier, promotes the dispersion of the active component and inhibits the loss of Zn species.