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A high-performance 3D hierarchical porous metal-free N-doped carbon catalyst toward the oxygen reduction reaction (ORR) in acidic medium was successfully synthesized by employing ZnO as a mesoporous template and NaCl as both a macroporous template and a structure protective agent. The resultant improved active site density and diffusion efficiency lead to a superior ORR activity with a half-wave potential high up to 0.755 V in 0.1 M HClO4. [ABSTRACT FROM AUTHOR]

Although continuously increased capacitance records have been reported, the rate performance of carbon based supercapacitors is still short of expectation. We herein present a facile but general surface engineering route, which is able to remarkably increase the rate capability by 26% on average, particularly for various carbon based materials. The adopted HNO3‐H2O2 acid treatment process introduces copious heteroatoms and transfers the surface to be superhydrophilic, which largely improve the accessible interior surface areas for higher capacitances under high current densities, thus producing better rate performances. [ABSTRACT FROM AUTHOR]

Abstract Studies indicated that the existing carbon supported Pt-based nanoalloys may exhibit instability and lose activity under acidic conditions due to particle aggregation, leaching/dissolution of the non-precious metals and carbon corrosion, which impeded the practical use of these nanomaterials for fuel cell electrocatalysts. This work presents a polyaniline (PANI)-confined space annealing strategy to efficiently promote the stability and activity of solution phase synthesized PtNi nanoparticles. By virtue of an in situ formed PANI coating layer, PtNi NPs can be developed to be more stable and active at thermal annealing process without serious agglomeration. Simultaneously, high temperature forces the carbonization of PANI, featuring the final obtained PtNi NPs with a nitrogen-doped carbon (NC) coating layer. XPS analysis attributed the enhanced catalytic performance of as-constructed PtNi/C@NC composite to the unique electronic interaction between Pt atoms and NC outer layer, which is beneficial for stabilizing PtNi NPs under fuel cell working condition. Graphical abstract Image 1 Highlights • PANI-confined space annealing makes solution phase synthesized PtNi NPs to be more stable and active. • The in situ polymerized PANI shell renders PtNi NPs with highly resistance toward sintering. • An electronic interaction between PANI-derived NC layer and Pt creates a stabilizing effect against Pt oxidation/dissolution. [ABSTRACT FROM AUTHOR]