Metal-Organic Framework-Derived PtNi on N-Doped Carbon Boosting Efficient Oxygen Electrocatalysis

Pt-TM (TM = Fe, Co, Ni, Cu, etc.) alloy catalysts, other than pure Pt, have been introduced as active catalysts for ORR. However, the synthesis of highly durable Pt alloy catalysts is still an enormous challenge. Herein we utilized pyrolyzed-MOF as a carbon support to fabricate PtNi nanoparticles with an average diameter of 3.1 nm. The as-synthesized Pt1Ni1/NC catalyst showed a higher ORR activity than commercial Pt/C (20 wt % Pt on carbon) in both alkaline and acidic solutions. Pt1Ni1/NC delivered a high mass activity of 2.16 A mg Pt-1, superior to Pt/C (0.105 A mg Pt-1) in 0.1 M KOH, and showed a high mass activity of 1.09 A mg Pt-1, superior to Pt/C (0.101 A mg Pt-1) in 0.1 M HClO4. Furthermore, Pt1Ni1/NC displayed excellent durability in both alkaline and acidic solutions, with minor decay in half-wave potential after 8000 cyclic voltammetry cycles. Zinc-air batteries (ZABs) assembled with Pt1Ni1/NC displayed a high specific capacity of 882 mAh gzn-1 and an energy density of 1102 Wh kgzn-1. A peak power density of 464 mW cm-2, higher than that of commercial Pt/C, is obtained for Pt1Ni1/NC-based ZAB. This work offers a innovative approach to synthesize precious-metal-based catalysts with promising activity and durability for applications in fuel cells and metal-air batteries.

Automated summary

PtNi nanoparticles supported by pyrolyzed-MOF show higher ORR activity and excellent durability in alkaline and acidic solutions, making them promising catalysts for fuel cells and metal-air batteries.