A Metal-Organic Framework-Derived Atomically Dispersed Yttrium as an Electrocatalyst for Oxygen Reduction Reaction

As a low-cost alternative to the platinum group metal-free electrocatalysts toward oxygen reduction reaction (ORR), single-atom catalysts (SACs) are gaining attention owing to their unique electronic structure, higher atom utilization efficiency, and improved catalytic activity. Herein, we report the design of a SAC for ORR featuring single atoms of yttrium anchored on a nitrogen-doped carbon matrix (Y-N-C) derived from the Y-doped zeolitic-imidazole framework. The catalyst with 2.93 wt % Y (ICP-OES) demonstrates efficient ORR activity and stability in 0.1 M KOH with onset (E-on) and half-wave (E-1/2) potentials of 0.931 and 0.770 V vs RHE, respectively. The catalyst retains 87% of its original current during the short-term stability test for 25 h, comparable to that of Pt/C. Furthermore, the catalyst also demonstrates good selectivity toward 4e(-) ORR with the electron-transfer number as high as 3.99 and H2O2 yield as low as 0.57% in the potential range 0.4-0.9 V vs RHE. Our work, with a facile one-step pyrolysis approach, adds one more candidate to the series of efforts being made in the pursuits of developing SACs for electrocatalytic applications.