Promotion of oxygen reduction by a bio-inspired tethered iron phthalocyanine carbon nanotube-based catalyst

Abstract

Electrocatalysts for oxygen reduction are a critical component that may dramatically enhance the performance of fuel cells and metal-air batteries, which may provide the power for future electric vehicles. Here we report a novel bio-inspired composite electrocatalyst, iron phthalocyanine with an axial ligand anchored on single-walled carbon nanotubes, demonstrating higher electrocatalytic activity for oxygen reduction than the state-of-the-art Pt/C catalyst as well as exceptional durability during cycling in alkaline media. Theoretical calculations suggest that the rehybridization of Fe 3d orbitals with the ligand orbitals coordinated from the axial direction results in a significant change in electronic and geometric structure, which greatly increases the rate of oxygen reduction reaction. Our results demonstrate a new strategy to rationally design inexpensive and durable electrochemical oxygen reduction catalysts for metal-air batteries and fuel cells.

Highly Active and Stable Pt–Pd Alloy Catalysts Synthesized by Room‐Temperature Electron Reduction for Oxygen Reduction Reaction

“…At present, carbon‐supported platinum (Pt) is still the widely used cathode catalyst in PEMFCs 2. However, for applications of the Pt/C catalyst, there are still some critical issues to be solved, including sluggish kinetics of the oxygen reduction reaction (ORR), the poor stability, and the expensive price 3. Therefore, a number of strategies have been proposed for enhancing the electrocatalytic properties and reducing the cost of Pt‐based catalysts, such as improving the carbon support,4 changing the morphologies of Pt nanoparticles,5 and synthesizing Pt–M alloy catalysts 6…”

Effects of Axial Coordination of the Metal Center on the Activity of Iron Tetraphenylporphyrin as a Nonprecious Catalyst for Oxygen Reduction

“…Similarly, polyvinylpyridine was reported to improve the kinetics of ORR catalyzed by a cobalt phthalocyanine in acidic media, 25 whereas iron phthalocyanine anchored through an axial pyridinic ligand to carbon nanotubes was demonstrated to outperform Pt as an ORR catalyst in alkaline solutions. 26 …”

Size-controlled large-diameter and few-walled carbon nanotube catalysts for oxygen reduction

“…5,[9][10][11][12] Recently, highly graphitized nitrogendoped nanocarbon materials derived from nitrogen-carbon precursors via a high-temperature approach in the presence of transition metals (TMs, e.g., Fe, Co, Ni) have attracted substantial attention due to their exceptionally high activity and stability compared to other NPMC formulations. 1,3,[13][14][15][16][17][18][19] According to other researchers and ourselves, [20][21][22][23][24][25][26][27][28] in situ formation of graphitized carbon nanostructures in the M-N-C catalysts is a critical factor dictating active site generation and is linked to the measured ORR activity. The currently prepared carbon nanostructures in M-N-C catalysts include tubes, onion-like carbon, and platelets (multi-layered graphene).…”