Electrochemical water splitting (EWS) is a highly clean and efficient method for high-purity hydrogen production. Unfortunately, EWS suffers from the sluggish and complex oxygen evolution reaction (OER) kinetics at anode. At present, the efficient, stable, and low-cost non-precious metal based OER electrocatalyst is still a great and long-term challenge for the future industrial application of EWS technology. Herein, we develop a simple and fast approach for gram-scale synthesis of flower-like cobalt-based layered double hydroxides nanosheet aggregates by ultrasonic synthesis, which show outstanding electrocatalytic performance for the oxygen evolution reaction in alkaline media, such as preeminent stability, small overpotential of 300 mV at 10 mA·cm^-2 and small Tafel slope of 110 mV·dec^-1.

Although nanostructures based on noble metal alloys are widely utilized in (electro)catalysis, their low-temperature synthesis remains an enormous challenge due to the different Nernst equilibrium potentials of metal precursors. Herein, we describe the successful synthesis of trimetallic PtRhNi alloy nanoassemblies (PtRhNi-ANAs) with tunable Pt/Rh ratios using a simple mixed cyanogel reduction method and provide a detailed characterization of their chemical composition, morphology, and structure. Additionally, the electrochemical properties of PtRhNi-ANAs are examined by cyclic voltammetry, revealing composition-dependent electrocatalytic activity in the ethanol oxidation reaction (EOR). Compared to a commercial Pt black electrocatalyst, optimized Pt₃Rh₁Ni₂-ANAs display remarkably enhanced EOR electrocatalytic performance in alkaline media.

Nanocrystals of Rh, an important member of the noble metal catalyst family, have wide applications in heterogeneous catalytic reactions. Controlling the morphology of these noble metal nanocrystals has become an effective strategy for improving their catalytic activity and durability. In this work, well-defined Rh nanodendrites with very thin triangular branches as subunits are synthesized using a facile diethylene glycol reduction method, assisted by polyethyleneimine as a complex-forming agent and surfactant. For the first time, the methanol oxidation reaction (MOR) on Rh nanocrystals with a well-defined morphology is investigated using various electrochemical techniques in an alkaline medium. Unexpectedly, the as-prepared Rh nanodendrites, with ultrathin nanosheet subunits, exhibit superior electrocatalytic activity and durability during the MOR in an alkaline medium, indicating that Rh nanocrystals with specific morphology may be highly promising alternatives to Pt electrocatalysts in the MOR in an alkaline medium.

The development of active and methanol-tolerant cathode electrocatalysts for the oxygen reduction reaction (ORR) is extremely important for accelerating the commercial viability of direct methanol fuel cells (DMFCs). In this work, we present an efficient and template-free route for facile synthesis of cyanide (CN^-)-functionalized PtNi hollow nanospheres (PtNi@CN HNSs) with a high alloying degree using a simple cyanogel reduction method at room temperature. The physical and electrocatalytic properties of the PtNi@CN HNSs were investigated by various physical and electrochemical techniques. The PtNi@CN HNSs exhibited significantly enhanced electrocatalytic activity, durability, and particular methanol tolerance for the ORR as compared to commercial Pt black, and thus they are promising cathode electrocatalysts for DMFCs.

Novel self-assembled architectures have received a growing amount of attention and have significant potential for application in catalysis/electrocatalysis. Herein, we take advantage of the unique coordination and self-assembly properties of arginine for the preparation of dendritic PtCu bimetallic nanoassemblies with tunable chemical composition and structure. Strong interactions between the arginine molecules are key in driving the self-assembly of primary nanocrystals. In addition, the strong coordination interactions between arginine and metal ions is responsible for the formation of Pt–Cu alloys. We also investigated the electrocatalytic activity of various dendritic PtCu bimetallic nanoassemblies towards the methanol oxidation reaction. Pt₃Cu₁ nanoassemblies exhibited excellent electrocatalytic activity and stability in comparison with other PtCu bimetallic nanoassemblies (Pt₁Cu₃, Pt₁Cu₁) and commercial Pt black, due to their unique dendritic structures and the synergistic effect between the Pt and Cu atoms.

Controllable self-assembly of noble metal nanocrystals is of broad interest for the development of highly active electrocatalysts. Here we report an efficient arginine-mediated hydrothermal approach for the high-yield synthesis of cube-like Pt nanoassemblies (Pt-CNAs) with porous cavities and rough surfaces based on the self-assembly of zero dimensional Pt nanocrystals. In this process, arginine acts as the reductant, structure directing agent, and linker between adjacent nanocrystals. Interestingly, the Pt-CNAs exhibit single-crystal structures with dominant {100} facets, as evidenced by X-ray diffraction. Based on electrocatalytic studies, the as-synthesized Pt-CNAs exhibit improved electrocatalytic activity as well as good stability and CO tolerance in the methanol oxidation reaction. The Pt-CNA's good performance is attributed to their unique morphology and surface structure. We believe that the synthetic strategy outlined here could be extended to other rationally designed monometallic or bimetallic nanoassemblies for use in high performance fuel cells.

Bimetallic core-shell nanostructures with porous surfaces have drawn considerable attention due to their promising applications in various fields, including catalysis and electronics. In this work, Au@Pd core-shell nanothorns (CSNTs) with rough and porous surfaces were synthesized for the first time through a facile co-chemical reduction method in the presence of polyallylamine hydrochloride (PAH) and ethylene glycol (EG) at room temperature. The size, morphology, and composition of Au@Pd CSNTs were investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDX), EDX mapping, and X-ray photoelectron spectroscopy (XPS). The electrochemical properties of as-synthesized Au@Pd CSNTs were also studied by various electrochemical techniques. Au@Pd CSNTs exhibited remarkably high electrocatalytic activity and durability for the oxygen reduction reaction (ORR) in the alkaline media, owing to the unique porous structure and the synergistic effect between the Au core and Pd shell.