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

Abstract

Comprehensive Summary Oxygen reduction reaction (ORR) is the pivotal portion in many electrochemical energy conversion and storage technologies. However, the complex mechanisms and sluggish kinetics of ORR have also become one of the key issues hindering the development and application of these technologies. Recently, single‐atom catalysts (SACs) with well‐defined atomic active centers and theoretical 100% atomic utilization have attracted broad interests in the area of electrocatalytic ORR. The electrocatalytic ORR performance of SACs is fundamentally determined by the intrinsic activity of the single‐atom active site and increasing the number of active sites involved in the ORR can further enhance the ORR activity of SACs. In this review, advances in atomically dispersed metal electrocatalysts for ORR in the last three years are summarized. Three main regulation strategies for achieving SACs with excellent intrinsic activity in the context of the ORR mechanism are involved including modulation of coordination environments, the construction of intrinsic defects, and the introduction of dual active sites. Moreover, discussions on improving the loading and utilization of active sites are given. Finally, the current challenges and opportunities for the development of SACs for ORR are presented.

Tin as a co-catalyst for electrocatalytic oxidation and reduction reactions

“…Typically, the binding energy between oxygen-containing species 42 and active sites, and the surface coverage of blocking materials are two critical descriptors for ORR performance. It is observed that the binding free energies of intermediates have a linear relationship.…”

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.…”

Promoting Electrocatalytic CO2 Reduction to CO via Sulfur‐Doped Co‐N‐C Single‐Atom Catalyst†

“…[ 8‐9 ] Recently, single‐atom catalysts have aroused increasing interests owing to their high atomic utilization efficiency and tunable coordination structure. [ 10‐13 ] Metal‐nitrogen‐carbon catalysts as one of the most typical SACs have attracted extensive attention for the CO 2 RR to produce CO. [ 14‐17 ] However, M‐N‐C catalysts usually exhibit poor CO 2 RR performance without further modification. Therefore, developing effective M‐N‐C catalysts for highly active CO 2 RR remains challenging yet urgent.…”