Nanoarchitectonics of cobalt/nitrogen-doped carbon with an unbalanced double primitive bicontinuous motif for...

In virtue of the smooth mass transfer and unique physical properties enabled by the special three-dimensional (3D) interconnected network, bicontinuous porous functional materials have received extensive attention in catalysis, energy conversion, and cargo delivery. However, endowing materials with meticulous inner bicontinuous geometries and achieving precise control over the pore structures remain a huge challenge. Herein, we report a facile heterogeneous interface-induced topological phase transition method to obtain unbalanced double primitive architectural cobalt/nitrogen-doped (Co/N-doped) carbon particles. The rationally designed dual metal-organic framework (MOF)-derived composite particles retain the original 3D channel with a single primitive cubic structure inherited from their precursors after the pyrolysis process. Noteworthily, a new set of continuous channels with the same topological structure is introduced into the originally solid pore wall by utilizing local thermal stability differences at the heterogeneous interface of two isostructural MOFs. The two sets of channels possess different volumes, presenting an unbalanced bicontinuous structure similar to Im3̄m, with the Co-N _x active sites anchored on the derived thin pore walls. Benefiting from the high-efficiency mass transfer enabled by the 3D open channels of the bicontinuous structure and high surface utilization enabled by the local thin-wall nanotube structure, unbalanced bicontinuous structural Co/N-doped carbon catalysts exhibit enhanced electrocatalytic activity in the oxygen reduction reaction (ORR). The assembled Zn-air battery delivers high peak power density (215 mW cm^-2) and large specific capacity (766 mA h g^-1). This methodology provides new insights for universally constructing extra channels to achieve 3D periodic interpenetrating networks from the rational structural design and processing of porous materials with appropriate heterogeneous interfaces.