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Combining the core-shell structure with the optimization of surface composition and structure in the shell is a fantastic strategy to enhance the electrocatalytic performances. Here, we synthesized trimetallic Au@PtxSny core-shell nanoparticles (NPs) with tunable composition and structure of Pt-Sn alloyed shells. Impressively, the Au@PtSn core-shell NPs with hexagonal PtSn alloyed shells exhibited the highest mass activity and specific activity toward ethanol oxidation reaction (EOR) in alkaline electrolyte, which are 13.0 and 12.7 times higher than those of the commercial Pt/C. In addition, the Au@PtSn core-shell NPs displayed the best stability compared to commercial Pt/C, with only 44.8% loss vs. 86.8% loss in mass activity after 1,000 s due to the stronger anti-poisoning ability for reaction intermediates. The theory calculations reveal that the introduction of Au core and alloying Pt with Sn both endow Pt with an appropriate d-band center, and thus effectively boosting the EOR activity.

Ru is a key component of electrocatalysts for hydrogen evolution reaction (HER), especially in alkaline media. However, the catalytic activity and durability of Ru-based HER electrocatalysts are still far from satisfactory. Here we report a solvothermal approach for the synthesis of PdCuRu porous nanoplates with different Ru compositions by using Pd nanoplates as the seeds. The PdCuRu porous nanoplates were formed through underpotential deposition (UPD) of Cu on Pd, followed by alloying Cu with Pd through interdiffusion and galvanic replacement between Cu atoms and Ru precursor simultaneously. When evaluated as HER electrocatalysts, the PdCuRu porous nanoplates exhibited excellent catalytic activity and durability. Of them, the Pd24Cu29Ru47/C achieved the lowest overpotential (40.7 mV) and smallest Tafel slope (37.5 mV dec−1) in an alkaline solution (much better than commercial Pt/C). In addition, the Pd24Cu29Ru47/C only lost 17% of its current density during a stability test for 10 h, while commercial Pt/C had a 59.5% drop under the same conditions. We believe that the electron coupling between three metals, unique porous structure, and strong capability of Ru for water dissociation are responsible for such an enhancement in HER performance.

Pd-based nanocrystals are a promising candidate as non-Pt electrocatalysts for oxygen reduction reaction (ORR), but their performance still has large room to be improved. Here, we have successfully synthesized Ga-doped Pd3Pb nanocubes with different amounts of Ga by a simple one-pot approach. When evaluated as electrocatalysts for ORR, the Ga-doped Pd3Pb nanocubes exhibited substantially enhanced catalytic properties in an alkaline media relative to the Pd3Pb nanocubes and commercial Pt/C. Interestingly, the Ga-doped Pd3Pb nanocubes showed a volcano-like relationship in ORR activity as a function of the amount of Ga with the 1.76% Ga-doped Pd3Pb nanocubes Pd3Pb/Ga-2 NC) being the best ORR electrocatalysts. Specifically, the Pd3Pb/Ga-2 NC/C exhibited the highest specific (7.57 mAcm-2) and mass activities (0.91 mAμgPd-1), which were 18.0 and 4.3 times higher than those of the commercial Pt/C. In addition, such Pd3Pb/Ga-2 NC/C displayed the higher durability with an increase of 14.2% in mass activity after 20000 cycles relative to commercial Pt/C (74.9% loss). This enhancement in both activity and durability can be attributed to the strong hybridization interactions and the formation of Pd shells on the surface by leaching of Pb. [ABSTRACT FROM AUTHOR]