Synthesis and electrocatalytic performance of nitrogen-doped macroporous carbons

Nitrogen-doped carbons with highly ordered macroporous structures are fabricated via the assembly and carbonization of polymethylmethacrylate (PMMA)-polyacrylonitrile (PAN) core-shell nanoparticles. During the carbonization, PMMA (acting as a template) is completely removed, and the resulting hollow PAN particles are fused to form ordered macroporous structures. Micropores are present on the macropore walls, providing desirable inter-macropore channels. The nitrogen atoms partially remain in the resulting carbon structures and exhibit mainly pyridinic and quaternary configurations under relatively high carbonization temperatures. The careful control of the pre-stabilization and carbonization conditions is crucially important for the formation of the ordered macroporous structures. As a demonstration, the obtained nitrogen-doped macroporous carbons exhibit excellent electrochemical catalytic activities both for the reduction of S_n^2- electrolyte ions in QDSSCs and the reduction of oxygen in fuel cells.