Controlling the nanostructures and chemical compositions of the electrochemical nanocatalysts has been recognized as two prominent means to kinetically promote the electrocatalytic performance. Herein, we report a general “dual”-template synthesis methodology for the formation of multimetallic hollow mesoporous nanospheres (HMSs) with an adjustable interior hollow cavity and cylindrically opened mesoporous shell as a highly efficient electrocatalyst for ethanol oxidation reaction. Three-dimensional trimetallic PdAgCu HMSs were synthesized via in situ coreduction of Pd, Ag, and Cu precursors on “dual”-template structural directing surfactant of dioctadecyldimethylammonium chloride in optimal synthesis conditions. Due to synergistic advantages on hollow mesoporous nanostructures and multimetallic compositions, the resultant PdAgCu HMSs exhibited significantly enhanced electrocatalytic performance toward ethanol oxidation reaction with a mass activity of 5.13 A mgPd–1 at a scan rate of 50 mV s–1 and operation stability (retained 1.09 A mgpd–1 after the electrocatalysis). The “dual”-template route will open a new avenue to rationally design multimetallic HMSs with controlled functions for broad applications.

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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.

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The rational design of the Au–support electronic interaction is crucial for Au nanocatalysis. We herein report our observation of electronic perturbation at the Au–carbon interface and its application in controlling the reaction selectivity in styrene oxidation. Ultrasmall Au nanocatalysts were grown in situ on a nitrided carbon support where the nitrogen-doped carbon supports enriched the surface charge density and generated electron-rich Au surface sites. The Au–carbon interaction altered the binding behavior of CC bonds to catalytic centers, leading to a solvent-polarity-dependent selectivity in CC oxidation reactions. A high selectivity of 90% to benzaldehyde was achieved in an apolar solvent, and a selectivity of 95% to styrene epoxide was attained in a polar solvent. The Au–carbon electronic perturbation, originating from surface functional groups on the carbon support, may provide an alternative avenue to tune the selectivity and activity of more complex reactions in heterogeneous catalysis.

This manuscript reports a facile yet effective surfactant-templated synthesis methodology to grow in situ metallic gold mesoporous nanospheres for methanol electrooxidation.

A one-pot soft-templating method is reported to fabricate nanosized bimetallic PdAg hollow mesoporous nanospheres (HMSs) for electrocatalytic ethanol oxidation reaction (EOR). The synthesis relies on the "dual-template" surfactant of dioctadecyldimethylammonium chloride that drives in situ growth of mesoporous frameworks on the surface of vesicles into the HMSs with radially opened mesochannels. The synthetic protocol is extendable to engineer elemental compositions and hierarchical nanostructures of PdAg nanoalloys. This system thus provides a direct yet solid platform to understand catalytic add-in synergies of PdAg HMSs toward electrochemical EOR. By evaluating compositional and structural features separately, bimetallic Pd 65 Ag 35 HMSs display the highest EOR activity with a mass activity of 4.61 A mg Pd −1

A general synthetic methodology is reported to grow ultrafine cobalt-based nanoparticles (NPs, 2-7 nm) within high-surface-area mesoporous carbon (MC) frameworks. Our design strategy is based on colloidal amphiphile (CAM) templated oxidative self-polymerization of dopamine. The CAM templates consisting of a hydrophobic silica-like core and a hydrophilic PEO shell can coassemble with dopamine and template its self-polymerization to form polydopamine (PDA) nanospheres. Given that PDA has rich binding sites such as catechol and amine to coordinate metal ions (e.g., Co), PDA nanospheres containing Co ions can be converted into hierarchical porous carbon frameworks containing ultrafine metallic Co NPs (Co@MC) using high-temperature pyrolysis. The CAM templates offer strong "nanoconfinements" to prevent the overgrowth of Co NPs within carbon frameworks. The yielded ultrafine Co NPs have an average size of <7 nm even at a very high loading of 65 wt %. Co@MC can be further converted into various oxides and sulfides, e.g., CoO, CoO, CoS and transition-metal doped bimetallic CoMS, without significantly changing the size of NPs. As a proof-of-concept application, the porous Co-based NPs@MC hybrids were used as electrode materials for supercapacitors, which exhibit excellent supercapacitive performance with outstanding long-term cycling stability, due to the features such as ultrafine size, controllable chemical compositions, hierarchical porous structures, and full coverage of conductive carbons.