Efficient quantum dots anchored nanocomposite for highly active ORR/OER electrocatalyst of advanced metal-air batteries

Defect‐Enriched Nitrogen Doped–Graphene Quantum Dots Engineered NiCo2S4 Nanoarray as High‐Efficiency Bifunctional Catalyst for Flexible Zn‐Air Battery

“…Especially, Tafel slopes normalized by the electrochemical active surface area (ECSA) (Figure S9, Supporting Information) further confirm that the N‐GQDs/NiCo 2 S 4 /CC catalyst possesses a higher intrinsic OER activity than NiCo 2 S 4 /CC catalyst due to the introduction of N‐GQDs. Based on these analyses, it is reasonable to consider that the engineering of 3D NiCo 2 S 4 nanoarray with N‐GQDs could offer more active sites and favor the adsorption of OH − and the desorption of O 2 by providing a thermodynamically favorable environment, thus boosting the OER catalytic activity . Remarkably, the current density retention of the N‐GQDs/NiCo 2 S 4 /CC catalyst at 1.6 V is 90.6% after 10 h (Figure f), which is better than those of NiCo 2 S 4 /CC (86.2%) and commercial Ir/C/CC (80.1%) catalysts, and superior to most reported carbon/Co‐based sulfide composite catalysts (Table S2, Supporting Information).…”

“…Based on the above characterizations, the NiCo 2 S 4 (311) crystal plane appears to have the highest exposure to the reaction and thus this plane was selected as the active surface for simulation because it is the highest exposure plane. In this study, the most likely ORR mechanism on the N‐GQDs/NiCo 2 S 4 /CC catalyst is considered as a four‐electron predominant pathway, in which the intermediate product of OOH* is first produced and simultaneously reduced into OH* at the interface between NiCo 2 S 4 and N‐GQDs . Based on the DFT calculations, the relative Gibbs free energy and the optimized structural configuration of NiCo 2 S 4 /CC and N‐GQDs/NiCo 2 S 4 /CC catalysts interacting with oxygen intermediates are depicted in Figure .…”

2D Nitrogen‐Doped Carbon Nanotubes/Graphene Hybrid as Bifunctional Oxygen Electrocatalyst for Long‐Life Rechargeable Zn–Air Batteries

“…Not only the scarcity and high‐cost of precious metal‐based electrocatalysts are the significant concerns, such as Pt/C for ORR and IrO x /RuO x for OER, but their insufficient catalytic bifunctionality and inferior durability are also the short‐slab . Consequently, these single‐function ORR and OER catalysts are frequently mixed to practice bifunctional oxygen electrocatalyst for discharging/charging process in the rechargeable Zn–air batteries . Therefore, developing efficient and robust bifunctional oxygen electrocatalysts is indispensable to accelerate the sluggish kinetics of oxygen reaction and further advance the rechargeability and stability of Zn–air batteries…”

NiFe Alloyed Nanoparticles Encapsulated in Nitrogen Doped Carbon Nanotubes for Bifunctional Electrocatalysis Toward Rechargeable Zn‐Air Batteries

“…The peaks with binding energy at 707.0 eV and 719.5 eV can be attributed to metallic Fe, [26] and the peaks at 710.0 eV and 722.0 eV are from Fe 3 + species along with two satellite peaks at 714.0 eV and 726.0 eV. [27,28] As a comparison, the high-resolution XPS spectra of the Fe 2p electrons for Fe 100 @N-CNTs can be found in Figure S7a, where somewhat similar patterns attributed to metallic Fe, Fe 3 + species, Fe satellite peaks can be seen upon deconvolution. The results imply the formation of iron oxide of Fe 2 O 3 inside the carbon nanotubes.…”