Metal–Organic Framework-Derived Mn/Ni Dual-Metal Single-Atom Catalyst for Efficient Oxygen Reduction Reaction

Abstract

Non-precious-metal-based oxygen reduction reaction (ORR) catalysts hold great prospects for rechargeable metal–air batteries and reversible electrolyzer/fuel cell systems. Among the various earth-abundant and noble-metal-free catalysts, Mn- and Ni-based single-atom catalysts (SACs) are attracting attention for ORRs. Herein, we designed a facile and efficient strategy to obtain Mn/Ni dual-metal single-atom catalysts, in which atomic Mn and Ni sites were dispersed on nitrogen-doped porous carbon. The optimized Mn/Ni catalysts showed excellent ORR electrocatalytic performance with a half-wave potential of 0.803 V, comparable to that of commercial Pt/C catalysts. Meanwhile, the electron transfer number was determined to be 3.9, indicating a good four-electron reaction process. The excellent electrocatalytic performance was attributed to the N-doped porous carbon structure with a large specific surface area, which afforded abundant active sites to anchor the single Mn and Ni atoms.

Atomically Dispersed Metal‐Nitrogen‐Carbon Electrocatalysts for the Oxygen Reduction Reaction

“…Notably, these central atoms such as Fe, Co, Ni, Cu, Cr, Mn and so on have been successfully coordinated with N to form M-N-C electrocatalysts for the ORR. [52,[79][80][81][82][83][84][85][86][87][88][89] However, distinct differences of these electrocatalysts in catalytic activity are observed. This discrepancy can be attributed to various factors, including the choice of an appropriate central metal and the specific coordination environment, both of which significantly impact the catalytic activity.…”

“…Meanwhile, the ORR activity of M-N-C electrocatalysts can be optimized by modifying the center metal and coordination environment. To date, a broad range of center metals (e. g., Fe, [15][16][17][18][19][20][21] Co, [22][23][24][25][26][27][28] Ni, [29][30][31][32][33][34] Cu, [35][36][37][38][39][40][41] Cr, [42][43][44][45] Mn, [46][47][48][49][50][51][52][53][54][55] etc.) have been developed, with particular emphasis on the Fe-N-C structure, which has drawn considerable attention for exhibiting superior ORR activity compared to Pt in alkaline solution.…”