Formation of Asymmetric Bowl-Like Mesoporous Particles via Emulsion-Induced Interface Anisotropic Assembly

Mesoporous colloidal particles with tailored asymmetric morphologies and radially oriented large channels are of great importance for development of new carriers for nanoencapsulation, high-performance mass transport nanosystems, and complex assembly structures. However, controllable anisotropic growth to asymmetric mesoporous particles is very challenging via the universal surfactant-directed soft-templating method. Herein we report a simple emulsion-induced interface anisotropic assembly approach to synthesize bowl-like mesoporous polydopamine particles with diameter of ∼210 nm, well-controlled radially oriented mesochannels, and large pore size of ∼11 nm. This interface-driven approach also creates opportunities for tailoring the assembly and formation of various asymmetric and symmetric polydopamine particles. Bowl-like mesoporous carbon particles with radially oriented channels, high accessible surface area of 619 m² g^-1, and large pore size of ∼8 nm can be fabricated by subsequent hydrothermal treatment and calcination under nitrogen atmosphere. Lastly, we demonstrate that the as-derived bowl-like mesoporous carbon particles manifest enhanced electrocatalytic performance for oxygen reduction reaction in alkaline electrolyte. © 2016 American Chemical Society.