Sustainable Hydrothermal Carbonization Synthesis of Iron/Nitrogen‐Doped Carbon Nanofiber Aerogels as Electrocatalysts for Oxygen Reduction

Abstract

It is urgent to develop new kinds of low-cost and high-performance nonprecious metal (NPM) catalysts as alternatives to Pt-based catalysts for oxygen reduction reaction (ORR) in fuel cells and metal-air batteries, which have been proved to be efficient to meet the challenge of increase of global energy demand and CO emissions. Here, an economical and sustainable method is developed for the synthesis of Fe, N codoped carbon nanofibers (Fe-N/CNFs) aerogels as efficient NPM catalysts for ORR via a mild template-directed hydrothermal carbonization (HTC) process, where cost-effective biomass-derived d(+)-glucosamine hydrochloride and ferrous gluconate are used as precursors and recyclable ultrathin tellurium nanowires are used as templates. The prepared Fe/N-CNFs catalysts display outstanding ORR activity, i.e., onset potential of 0.88 V and half-wave potential of 0.78 V versus reversible hydrogen electrode in an alkaline medium, which is highly comparable to that of commercial Pt/C (20 wt% Pt) catalyst. Furthermore, the Fe/N-CNFs catalysts exhibit superior long-term stability and better tolerance to the methanol crossover effect than the Pt/C catalyst in both alkaline and acidic electrolytes. This work suggests the great promise of developing new families of NPM ORR catalysts by the economical and sustainable HTC process.

Atomic Fe–Nx Coupled Open‐Mesoporous Carbon Nanofibers for Efficient and Bioadaptable Oxygen Electrode in Mg–Air Batteries

“…Therefore, a combination of the open‐mesoporous and interconnected structures in catalyst for improving mass transport properties and the 3D porous channels and networks in cathode for boosting air diffusion is highly desired . With respect to diverse nanostructured porous carbon catalysts, carbon nanofibers (CNFs) exhibit nanoscale diameter, high aspect ratio, interconnected nanofibrous networks for ions and air diffusion, and continuous conductive pathways for electron transport, which thus facilitate the electrocatalytic kinetics of the air cathode . However, these currently reported CNFs mainly possess microporous structures, the incorporation of open mesopores and interconnected channels in CNFs via cost‐effective and facile method is quite challenging.…”

Macroscopic‐Scale Three‐Dimensional Carbon Nanofiber Architectures for Electrochemical Energy Storage Devices

“…To extend the template-directed assembly for preparing metal/N-doped CNFs, we employed the abundant and economical carbohydrate salts of D-(+)-glucosamine hydrochloride and ferrous gluconate as molecular precursors to prepare the Fe/N-containing CNF aerogels using TeNWs as the template. [78] Benefiting from the homogeneous distribution of iron/nitrogen precursors on the molecular level in the carbonaceous matrix, the further pyrolysis and leaching treatment of the products result in Fe/N uniformly doped CNF catalysts (Fe/N-CNF) with abundant FeN x active sites and ideal porous structures. Consequently, the as-prepared Fe/NCNFs catalysts display comparable ORR activity to commercial Pt/C catalyst in alkaline media.…”

Green‐Synthesized Nitrogen‐Doped Carbon‐Based Aerogels as Environmentally Friendly Catalysts for Oxygen Reduction in Microbial Fuel Cells

“…Many other works report Ndopingo fc arbonm aterials,d oped or not by other heteroatoms,f or different applications,i ncluding MFCs. [24][25][26][27] To the best of our knowledge,t he highestp erformancef or these materials in MFCsa re those published by Zhange tal. [28] In any case,t he precursors and/or the synthesis strategies used are not completely environmental friendly and/or not as cheap as the scale-up process requires in order to put MFCs on the market.…”