Nanoreactor of Nickel‐Containing Carbon–Shells as Oxygen Reduction Catalyst

Abstract

A Pt-free nanoreactor, consisting of N-doped hollow carbon nanocapsules with encapsulated Ni nanoparticles, is developed for high-performance oxygen reduction reaction (ORR) catalyst. The nanoreactor effect improves its catalytic activity for ORR mainly in a 4e pathway. The presence of Ni nanoparticles within the nanoreactor significantly enhances the stability with a current retention of 90% after 40 h.

Modifying Commercial Carbon with Trace Amounts of ZIF to Prepare Derivatives with Superior ORR Activities

“…Metal oxide nanoparticles, metal-N 4 complexes, metal-C-N moieties, and defects of the carbon substrates could all independently function as active centers, but it is unknown which of these centers is best for ORR. The methods to enhance electrochemical activities mainly rely on four aspects: (1) increasing the intrinsic activities of active centers, [23][24][25] (2) augmenting the amount or concentration of active centers, [25][26][27] (3) optimizing mass transfer during the reaction, [28,29] (4) enhancing the conductivity of catalysts. [10][11][12][13][14] Such catalysts should be further explored to fulfill the requirements of cell optimizations and applications.…”

“…[20] However, graphene and carbon nanotubes are not cheap, which have impeded practical applications. The methods to enhance electrochemical activities mainly rely on four aspects: (1) increasing the intrinsic activities of active centers, [23][24][25] (2) augmenting the amount or concentration of active centers, [25][26][27] (3) optimizing mass transfer during the reaction, [28,29] (4) enhancing the conductivity of catalysts. Vulcan XC72 conductive carbon black (VXC72) is one of the most widely used carbon materials in fuel cells due to its good dispersibility, large surface area, and high conductivity.…”

Designed Echinops‐Like Ni@NiNC as Efficient Bifunctional Oxygen Electrocatalyst for Zinc‐Air Batteries

“…Deconvoluted N 1s peak (Figure c) corresponding to pyridinic‐N (398.1 eV), Ni−N (398.8 eV), pyrrolic‐N (399.7 eV) and graphitic‐N (401.3 eV) indicated a successful N‐doping in the composite . Ni survey spectrum in Figure d showed Ni (852.7 eV), Ni 2p 3/2 Ni−N (854.2 eV) and Ni−O (855.9 eV), Ni 2p 1/2 Ni−N (871.5 eV) and Ni−O (873.0 eV) . The distinct Ni−N bonds in N 1s and Ni 2p spectra together with EDS mapping results confirmed the presence of Ni–N sites in Ni@NiNC‐600.…”

“…Polarization curves in Figure S8 showed that the ORR activity of Ni@NiNC‐600 decreased evidently in the presence of SCN − , whereas the OER activity of Ni@NiNC‐600 without obvious change. This result suggested that Ni–N active sites could be an important role for ORR activity …”

Confinement of Reactive Oxygen Species in an Artificial‐Enzyme‐Based Hollow Structure To Eliminate Adverse Effects of Photocatalysis on UV Filters

“…The void space in hollow particles has been proven to modulate the refractive index, lower density, increase active area for catalysis, and improve the anticancer immunity . Recently, nitrogen‐doped hollow carbon nanocapsules with encapsulated nickel nanoparticles were proven to show superior activity in the oxygen reduction reaction . The high performance was attributed to the hollow structure, which could confine oxygen inside a conformal space and allowed more effective collision frequency with catalysts.…”