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Pt-based electrocatalysts are by far the most effective for the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR), but they still suffer from high cost and insufficient overall performance. Improving Pt utilization via alloying or by forming core@shell structures is important for enhancing Pt activity and overall electrocatalytic performance. Herein, we report a simple seed-mediated method for synthesizing a dodecahedral PtCu alloy atomic shell on Pd nanocrystals. Significantly, such a Pd@PtCu nanocomposite with unique core@alloy-shell structure achieves a 25-fold and 6-fold enhancement of mass activity for HER and ORR, respectively, compared with the commercial Pt/C catalyst in acid media. Moreover, the unique Pd@PtCu catalyst shows only 1.0 mV increase in overpotential at 10 mA cm–2 after 10 000 cycles for HER and almost no activity decay after 5 000 cycles for ORR, indicating the high endurance of Pd@PtCu in the electrochemical environment.

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Carbon materials, with a controllable structure, derived from metal-organic frameworks (MOFs) have emerged as a new class of electrocatalysts in renewable energy devices. However, efficient conversion of MOFs to small diameter doped carbon nanotubes in inert gases at high temperatures (>600 °C) remains a significant challenge. In this study, we first report the growth of small diameter cobalt and nitrogen co-doped carbon nanotubes (Co/N-CNTs) from mesoporous silica (mSiO2)-coated Co-based MOFs (ZIF-67). The presence of a layer of mSiO2 outside the ZIF-67 nanocrystals prevents the Co nanocatalysts from quick aggregation, and significantly serves as a unique 'sieve' for inducing the catalytic growth of CNTs during pyrolysis. The obtained Co/N-CNTs, with ∼13 nm diameter evolved from the pristine MOF architecture, exhibit higher catalytic activity and stability for oxygen reduction than commercial Pt/C electrocatalysts in alkaline media. This novel strategy opens a new avenue for the synthesis of Co/N-CNTs with great promise for developing high performance and cheap electrocatalysts.