Hollow palladium–copper bimetallic nanospheres with high oxygen reduction activity

Applications of bimetallic PdCu catalysts

Bimetallic PdCu nanoparticles can be applied as catalysts in a wide range of chemical and electrochemical reactions.

Bimetallic alloy and semiconductor support synergistic interaction effects for superior electrochemical catalysis

The design and fabrication of economically viable anode catalysts for the methanol oxidation reaction (MOR) have been challenging issues in direct methanol fuel cells (DMFCs) over the decades. In this work, a composite electrochemical catalyst of Pd-coupled Ag and ZnO for the possible replacement of expensive Pt catalysts in DMFCs is successfully prepared. The as-made Pd@Ag/ZnO exhibits specific activity, which is 1.8-fold, 2.8-fold, and 4.6-fold higher than that of a Pd/ZnO catalyst, 20% Pd/C catalyst and Pd black, respectively. The improvement of the catalytic mechanism is likely due to the synergistic interaction between Pd@Ag and ZnO. The density functional theory (DFT) calculation results confirm that Ag doped into Pd weakens the adsorption of CO, dramatically improving the capability to resist CO poisoning.

Hollow Echinus-like PdCuCo Alloy for Superior Efficient Catalysis of Ethanol

Large-scale preparation of hollow echinus-like PdCuCo alloy nanostructures (HENSs) with a high surface area-to-volume ratio, rich active sites, and relatively efficient catalytic activity has attracted considerable research interest. Herein, we present an economic and facile approach to synthesize HENSs by galvanic exchange reactions using Co nanospheres as sacrificial templates. Moreover, the catalytic activity could be adjusted via changing the composition of the catalyst. The composition, morphology, and crystal structure of the as-obtained nanomaterials are characterized by various techniques, such as inductively coupled plasma atomic emission spectrometry, transmission electron microscopy, and X-ray diffraction. Electrochemical catalytic measurement results prove that the Pd₇₅Cu₈Co₃ catalyst obtained under optimal preparation conditions exhibits 10-fold higher activity for ethanol oxidation in comparison with the commercially available 20% Pd/C catalyst. The eminent performance of the Pd₇₅Cu₈Co₃ electrochemical catalyst could be ascribed to the peculiar echinus-like nanostructures.

Enhanced Oxygen Reduction Reaction by In Situ Anchoring Fe₂N Nanoparticles on Nitrogen-Doped Pomelo Peel-Derived Carbon

The development of effective oxygen electrode catalysts for renewable energy technologies such as metal-air batteries and fuel cells remains challenging. Here, we prepared a novel high-performance oxygen reduction reaction (ORR) catalyst comprised of Fe₂N nanoparticles (NPs) in situ decorated over an N-doped porous carbon derived from pomelo peel (i.e., Fe₂N/N-PPC). The decorated Fe₂N NPs provided large quantities of Fe-N-C bonding catalytic sites. The as-obtained Fe₂N/N-PPC showed superior onset and half-wave potentials (0.966 and 0.891 V, respectively) in alkaline media (0.1 M KOH) compared to commercial Pt/C through a direct four-electron reaction pathway. Fe₂N/N-PPC also showed better stability and methanol tolerance than commercial Pt/C. The outstanding ORR performance of Fe₂N/N-PPC was attributed to its high specific surface area and the synergistic effects of Fe₂N NPs. The utilization of agricultural wastes as a precursor makes Fe₂N/N-PPC an ideal non-precious metal catalyst for ORR applications.

Structural Regulation of PdCu2 Nanoparticles and Their Electrocatalytic Performance for Ethanol Oxidation

Two types of PdCu₂ nanoparticles were prepared through one-pot synthesis and a two-step reducing process, named as PdCu₂-1 and PdCu₂-2, respectively. The morphology and structure of as-prepared samples were investigated by transmission electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and inductively coupled plasma-optical emission spectrometry. Results showed that more Pd atoms were buried in the inside of PdCu₂-1, whereas more available Pd sites were distributed on the surface of PdCu₂-2. The electrochemical measurements indicated that both PdCu₂-1 and PdCu₂-2 nanoparticles showed a higher electrocatalytic activity than that for pure Pd nanoparticles. In particular, PdCu₂-2 predictably exhibited a better stability and durability as well as a lower onset potential and a higher catalytic current density than that of PdCu₂-1 toward ethanol oxidation in alkaline media. On the basis of these studies, the formation mechanisms of both the PdCu₂ catalysts and the relationship between their structure and properties were discussed in this paper.

Nanoporous PdCr alloys as highly active electrocatalysts for oxygen reduction reaction

The NP–Pd₇₅Cr₂₅ alloy exhibits superior ORR activities with enhanced specific and mass activities as well as higher structural stability.