Microstructure Engineering of Fe/FeC-Decorated Metal-Nitrogen-Carbon Mesoporous Nanospheres via a Self-Template Method for Enhancing Oxygen Reduction Activity.

We report a self-template and facile pyrolysis method to synthesize Fe/FeC-decorated metal-nitrogen-carbon mesoporous nanospheres, of which preserved plum-like and hollow structures can be simply engineered via controlling the thickness of the outermost polydopamine layer in the precursors. The preserved plum-like structure is demonstrated to show a large electrochemically active surface area and facilitate fast charge transfer, in comparison with the hollow one. The catalytic activities of metal-nitrogen-carbon and nitrogen-doped carbon active sites in the outer carbon layer toward oxygen reduction are improved under the activation of the encased Fe species.

Coordination-Assisted Polymerization of Mesoporous Cobalt Sulfide/Heteroatom (N,S)-Doped Double-Layered Carbon Tubes as an Efficient Bifunctional Oxygen Electrocatalyst.

It is a critical challenge to construct efficient precious-metal-free bifunctional oxygen electrocatalysts for fuel cell and metal-air batteries via structural and component engineering. Herein, a one-dimensional mesoporous double-layered tubular structure, where CoS nanocrystals are incorporated into nitrogen, sulfur codoped carbon, is successfully synthesized via the coordinated-assisted polymerization and sacrificial template methods. The double-layered tubular structure provides for a large electrochemically active surface area and promotes fast mass transfer.

Urchin-like non-precious-metal bifunctional oxygen electrocatalysts: Boosting the catalytic activity via the In-situ growth of heteroatom (N, S)-doped carbon nanotube on mesoporous cobalt sulfide/carbon spheres.

We successfully design and construct urchin-like non-precious-metal bifunctional oxygen electrocatalysts via a two-step pyrolysis process, where nitrogen, sulfur co-doped carbon nanotube frameworks are grafted onto mesoporous cobalt sulfide/nitrogen, sulfur co-doped carbon spheres. The urchin-like structure grants large electrochemically active area, good electron and mass transfer capability, as well as excellent structural stability. Nitrogen, sulfur co-doped carbon can synergistically enhance the catalytic activity of cobalt sulfide sites, and also contribute to the exposure of heteroatom-induced active sites, such as, pyridinic N, graphitic N, and C-S-C.