Assembly of hollow mesoporous nanoarchitectures composed of ultrafine Mo ₂C nanoparticles on N-doped carbon nanosheets for efficient electrocatalytic reduction of oxygen

Abstract

A simple method is developed to prepare Mo ₂C-embedded mesoporous N-doped carbon nanosheets which assemble into hollow spheres.

Abstract

A simple method is developed to assemble Mo ₂C nanocrystals on the surfaces of hollow, highly conductive mesoporous nanoparticles. Diblock copolymer (PS- b-PEO) micelles are used as templates to assist in the fast complexation of molybdate (MoO ₄ ²⁻) and polydopamine (PDA) precursors to make hollow precursor MoO ₄ ²⁻/PDA/PS- b-PEO particles. Then these particles are carbonized to generate mesoporous N-doped carbon nanosheets riddled with ultrafine molybdenum carbide (Mo ₂C) nanoparticles (MMo ₂C/NCS). An N-doped carbon matrix serves as an electron conductor and helps to prevent the aggregation of the Mo ₂C nanoparticles. The Mo ₂C nanoparticles in turn enhance the catalytic performance for the oxygen reduction reaction (ORR). The unique mesoporous 2D nanosheet and its derived 3D hollow structure expose numerous active catalytic sites while enabling free diffusion of the electrolyte and mass transfer. Based on these properties, MMo ₂C/NCS show enhanced catalytic activity for the ORR.