An Active Hybrid Electrocatalyst with Synergized Pyridinic Nitrogen‐Cobalt and Oxygen Vacancies for Bifunctional Oxygen Reduction and Evolution

Abstract

Main observation and conclusion A hybrid bifunctional oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) NiCo2O4–x/NLG with rich pyridinic‐nitrogen‐ cobalt coordination and oxygen vacancies was synthesized via a combination of the hydrothermal method and pulsed laser irradiation. NiCo2O4–x/NLG exhibits an excellent catalytic activity with a low overpotential of 290 mV at 10 mA·cm–2 for OER and a high half‐wave potential of 0.85 V for ORR. As a result, the overall ORR/OER overpotential of NiCo2O4–x/NLG is only 0.67 V in 1.0 mol/L KOH electrolyte, which is superior to commercial noble‐metal‐based catalysts (Pt/C+RuO2). It is evidenced that the enhanced intrinsic OER and ORR activities of NiCo2O4–x/NLG are attributed to a synergistic effect between the pyridinic‐N‐Co coordination and the oxygen vacancies. This work provides a new design strategy for enhancing the intrinsic activity of bifunctional ORR/OER electrocatalysts.

Applications of Rare Earth Promoted Transition Metal Sulfides in Electrocatalysis†

“…ORR is a two electron or four electron cathode half reaction of polymer electrolytic membrane fuel cell and rechargeable metal air cell, but its slow dynamics limits the power output. [ 107‐109 ] ORR reaction can be divided into direct reaction pathway and continuous reaction pathway. [ 110 ] The direct reaction pathway is 4 electron reaction to produce water.…”

Recent Developments of Atomically Dispersed Metal Electrocatalysts for Oxygen Reduction Reaction†

“…[ 67 ] The imperfect surface of carbon matrix in the presence of intrinsic defects can facilitate the anchoring and local electron density rearrangement of the central metal atom, thus the intrinsic defects engineering is also of extraordinary significance for optimizing the intrinsic catalytic activity of SACs. [ 68 ] Currently, the edge‐carbon defects are mainly constructed by removing metallic aggregates from the carbon matrix, or by activating the carbon substrate directly.…”

Hollow CoO Nanoparticles Embedded in N‐doped Mesoporous Graphene for Efficient Oxygen Reduction Reaction

“…Therefore, it is urgent to design and prepare non‐precious‐metal catalysts with high ORR activity and durability to replace Pt‐based catalysts [6,7] . Recently, it has been proved by theoretical and experimental results that heterojunction material of transition metals/metal oxides is also an important class of ORR catalyst with promising activity and reliability in alkaline solution [8–12] …”

“…[6,7] Recently, it has been proved by theoretical and experimental results that heterojunction material of transition metals/metal oxides is also an important class of ORR catalyst with promising activity and reliability in alkaline solution. [8][9][10][11][12] Among the transition metals, cobalt and its oxides are found to exhibit excellent electrocatalytic activity for ORR. [13][14][15][16][17] In addition, carbon-based nanomaterials are well known as the promising matrix for the synthesis of hybrid materials due to their high conductivity, large surface area and structural flexibility.…”