Metal Electrocatalysts For Oxygen Reduction Reaction Research Articles

Preparation of Co[sbnd]N co-doped carbon nanosheets electrocatalyst for efficient oxygen reduction reaction in zinc-air battery

It is very vital that there be a high-activity and serviceable catalyst for the oxygen reduction reaction (ORR) in the Zn-air Battery. Herein, utilizing g-C3N4 as a self-sacrifice template and Cobalt-His framework as the precursor, a simple strategy was developed to synthesize Co/N co-doped carbon nanosheets (CoNC 800) as a metal electrocatalyst for ORR. Due to the Co/N co-doped CoNX site and large specific surface area, the acquired materials show a preeminent ORR catalytic activity with an initial potential (~0.96 V) and half-wave potential (E1/2) of 0.85 V (vs. RHE) in an alkaline medium. Most importantly, the material has superior long-term stability and methanol tolerance than Pt/C. Furthermore, we assembled the Zn-air battery employing catalyst as an air cathode catalyst, demonstrating maximum power densities of 144 mWcm−2, a specific capacity of 821.50 Wh·kg−1, and charge/discharge cycle stability of more than 140 h. The nanosheet structure electrocatalysts derived from the Cobalt-His framework and g-C3N4 provide an innovative and instructive approach to the design of diverse nanomaterials.

Using Anion‐Exchange to Induce the Formation of Edge Defects in CoNx to Enhance ORR Activity

AbstractDeveloping high‐efficiency non‐noble metal based electrocatalysts to promote oxygen reduction reaction (ORR) is critical for the popularization of energy conversion devices. Herein, a facile anion exchange‐pyrolysis two‐step strategy is reported to synthesize hierarchical CoNx/Co@NC electrocatalyst with abundant edge defects. The introduction of edge defects not only alter the configuration of N species in carbon skeleton, but also can effectively trap metal Co atoms to form CoNx sites that can afford more adsorption sites for oxygen molecules. Furthermore, the incorporation of edge defects can trigger the change of electronic structure CoNx/Co@NC, which optimize the binding energy between oxygen intermediates and catalysts. Benefit from the increased active sites and the optimized electronic structure, the obtained edge defects‐rich CoNx/Co@NC demonstrates superior electrocatalytic activity, high durability and methanol tolerance with negligible decay after 40000 s, superior to Co@NC and commercial Pt/C. This job offers a valid anion exchange strategy for designing highly active non‐noble metal electrocatalysts for ORR.