Platinum (Pt)-based membrane electrode assembly (MEA) catalysts with high performance under operating proton exchange membrane fuel cells (PEMFCs) conditions are a prerequisite for practical applications. As indicated by theoretical calculations, lattice expansion in zinc (Zn)intercalated Pt alloys can weaken the adsorption of oxygen intermediates, enabling strong electronic interaction for boosting MEA catalysis. To test this hypothesis, herein, a new class of carbon (C)-supported ultrafine Pt alloys with the assistance of Zn is explored. Detailed characterizations indicate that the introduction of Zn can reduce the particle size, and simultaneously intercalates into the Pt alloys, resulting in the lattice expansion for enhancing metallic state of Pt and lowering d-band center. This intercalation strategy can be extended to PtNi, PtCo, as well as Pt. As a result, the optimized Zn-PtNi/C exhibits superior MEA activity (937.6 mW cm −2 of peak power density), much higher than those of corresponding PtNi/C (771.6 mW cm −2 ) and commercial Pt/C (700.7 mW cm −2 ) under the harsh operating fuel cell conditions. This work opens up a new avenue for creating high-performance PEMFC catalysts in terms of lattice engineering.
Amorphous metals and alloys are promising candidates for superior catalysts in many catalytic and electrocatalytic reactions. It is of great urgency to develop a general method to construct amorphous alloys and further clarify the growth mechanism in a wet-chemical system. Herein, inspired by the conservation of energy during the crystallization process, amorphous PdCu nanoalloys have been successfully synthesized by promoting the chemical potential of the building blocks in solution. Benefiting from the abundant active sites and enhanced corrosion resistance, the synthesized amorphous PdCu nanostructures exhibit superior catalytic activity and durability over the face-centered cubic one in formic acid decomposition reaction. More importantly, the successful fabrications of amorphous PdFe, PdCo, and PdNi further demonstrate the universality of the above strategy. This proposed strategy is promising to diversify the amorphous family.
Although distorted crystals are ubiquitous in nature, the artificial creation of distorted nanoscale crystals with tailored morphology and structure are greatly challenging, since the formation of ideal nanocrystals requires extremely rigorous condition. We herein demonstrate a kineticsinduced orientational morphological evolution of distorted Pd 20 Sb 7 rhombohedral nanocrystals (RNCs) by altering the temperature for growth. Detailed characterizations and experiments show that the retarded kinetics leads to the morphological evolution from regular rhombohedron to distorted rhombohedron, while the crystalline structure is kept identical by exposing six {211} facets. Moreover, the morphological evolution of distorted Pd 20 Sb 7 RNCs is further validated by the similar normalized activity towards formic oxidation reaction based on the surface Pd atoms. This work advances the precisely controlled synthesis of Pd-based nanocrystals with tailored morphologies, which may attract great interests in various fields including chemistry, materials science, catalysis and beyond.
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