Alloying palladium (Pd) catalysts with various metalloid and nonmetal elements can improve their catalytic performance in different chemical reactions. However, current nanosynthesis methods can only generate Pd alloys containing one metalloid or nonmetal, which limits the types of element combinations that may be used to improve Pd-based nanocatalysts. Herein, we report a simple soft-templating synthetic strategy to co-alloy Pd with the metalloid boron (B) and the nonmetal phosphorus (P) to generate ternary PdBP mesoporous nanospheres (MSs) with three-dimensional dendritic frameworks. We use a onestep aqueous synthesis method where dimethylamine borane and sodium hypophosphite serve as the B and P sources, respectively, as well as the co-reducing agents to drive the nucleation and growth of ternary PdBP alloy on a sacrificial dioctadecyldimethylammonium chloride template. The concentration of metalloid to nonmetal and the diameters of dendritic MSs can be tailored. The synthetic protocol is also extended to other multicomponent PdMBP alloy MSs to generate different types of dendritic mesoporous frameworks. Boron and phosphorus are known to accelerate the kinetics of the electrochemical oxygen reduction reaction (ORR) and alcohol oxidation reactions (AORs), because their alloys promote the decomposition of oxygen-containing intermediates on Pd surfaces. The dendritic mesoporous morphology of the ternary PdBP MSs also accelerates electron/mass transfer and exposes numerous active sites, enabling better performance in the ORR and AORs. Extending the surfactant-templating synthetic route to multiple types of elements will enable the generation of libraries of multicomponent metal−metalloid-nonmetal alloy nanostructures with functions that are suitable for various targeted applications.

Mesoporous colloidal nanospheres with tailorable asymmetric nanostructures and multimetallic elemental compositions are building blocks in next-generation heterogeneous catalysts. Introducing structural asymmetry into metallic mesoporous frameworks has never been demonstrated, but it would be beneficial because the asymmetry enables the spatial control of catalytic interfaces, facilitates the electron/mass transfer and assists in the removal of poisonous intermediates. Herein, we describe a simple bottom-up strategy to generate uniform sub-100 nm multimetallic asymmetric bowl-shaped mesoporous nanospheres (BMSs). This method uses a surfactant-directed "dual"-template to control the kinetics of metal reduction on the surface of a vesicle, forming mesoporous metal islands on its surface whose spherical cone angle can be precisely controlled. The asymmetric BMS mesostructures with different spherical cone angles (structural asymmetries) and elemental compositions are demonstrated. The high surface area and asymmetric nature of the metal surfaces are shown to enhance catalytic performance in the alcohol oxidation reactions. The findings described here offer novel and interesting opportunities for rational design and synthesis of hierarchically asymmetric nanostructures with desired functions for a wide range of applications.

This work presents a surfactant-directed aqueous synthesis to generate binary Pd–B mesoporous nanospheres for boosting ethanol oxidation electrocatalysis.

A facile solution-phase synthetic approach is reported to engineer the size effect of sub-100 nm PdAgCu mesoporous nanospheres in ethanol electrooxidation.

Alloying is one of the most promising routes for tuning the physicochemical properties of noble metal-based nanocatalysts and thus improving their (electro)catalytic performance. Despites numerous achievements, bimetallic and trimetallic nanoalloys have still been thoroughly studied for the past two decades. In this study, metalloid boron (B) was alloyed within palladium (Pd)-based nanocatalysts to promote the electrochemical ethanol oxidation reaction (EOR) in alkaline media. The optimum PdCuB nanocatalyst exhibited remarkable electrochemical EOR activity (5.83 A mg Pd −1 ) and good operation stability (both cycling and chronoamperometric studies). Mechanistic studies in both pure KOH and a KOH/ethanol mixture attributed superior EOR performance to positive synergistic effects of B in Pd-based nanocatalysts that kinetically accelerated the removal of poisoning ethoxy intermediates (the ratedetermining step of EOR). They included (i) an electronic effect that changed the electronic structure of Pd and thus weakened the adsorption of poisoning ethoxy intermediates, (ii) a bifunctional effect that facilitated the adsorption of OH ads and thus kinetically accelerated the further oxidation of poisoning intermediates, and (iii) a structural effect in which smaller B interstitially inserted into Pd-based nanocrystals and thus suppressed the physical Ostwald ripening processes.