An unusual network of α-MnO2 nanowires with structure-induced hydrophilicity and conductivity for improved electrocatalysis

Nanowires with anisotropic morphologies have been applied in various scientific and technological areas. It is also widely employed to fabricate nanowires into high-dimensional superstructures (arrays, networks etc.) to overcome the shortcomings of low-dimensional nanowires. However, typical strategies for constructing these superstructures are restricted to complicated and harsh synthetic conditions, not to mention unique 3D structures with advanced properties beyond common superstructures. Herein, we report an unusual network of α-MnO2 nanowires with structure-induced hydrophilicity and conductivity. In the network, the nanowires are interconnected from all directions by nodes, and the 3D network structure is formed from the endless connection of nodes in a node-by-node way. The unique network structure brings about high hydrophilicity and conductivity, both of which are positive factors for an efficient electrocatalyst. Accordingly, the α-MnO2 network was tested for electrocatalytic water oxidation and showed significantly enhanced activity compared with isolated α-MnO2 nanowires and 3D α-MnO2 microspheres. This study not only provides a synthetic route toward an advanced network structure but also a new idea for the design of materials for electrochemistry with both efficient mass diffusion and charge transfer.