A team of researchers from the School of Chemistry and Materials Science of Nanjing Normal University has found a feasible electrospinning approach to concurrently synthesize CoFe2O4 nanoparticles homogeneously embedded in 1D N-doped carbon nanofibers (denoted as CoFe2O4@N-CNFs). The results were published in the journal Advanced Science on 7 August 2017 and reported by Materials Views which is the web site of Wiley database.
“The purpose of our research is to find out an oxygen evolution electrocatalyst which is highly efficient and of low costs. The challenge of this research is how to make such an electrocatalyst in a smarter and easier way on the basis of the existing research. Fortunately, we made it by the employment of electrospinning technology.” Tongfei Li, the graduate student in the school of Chemistry and Materials Science said.
Electrocatalytic oxygen evolution reaction (OER) has stimulated considerable research interests due to its pivotal roles in various sustainable energy conversion and storage devices. However, to date, commercial electrocatalysts for OER still rely on the precious metal oxides, such as IrO2 and RuO2. Unfortunately, their extremely high costs and scarce reserve as well as insufficient long-term stability greatly impede their widespread applications and scalable commercialization in electrochemical energy devices. As such, it is extremely important to exploit earth-abundant and low-cost alternative catalysts with high activity and durability comparable or even superior to IrO2/RuO2 benchmarks for OER.
“Benefitting from the 1D structural feature and synergy of CoFe2O4 species of and N-doped carbon nanofibers, the as-synthesized CoFe2O4@N-CNFs exhibits remarkable OER performance in 0.1 MKOH medium with relatively low overpotential, much improved current density, favorable reaction kinetics, and outstanding long-term stability, as compared with the single-component counterparts (pure CoFe2O4 and N-CNFs) and the commercial RuO2electrocatalyst.” Lin Xu, the professor of the School of Chemistry and Materials Science, said.
By integrating the catalytically active CoFe2O4nanoparticles with the N-doped carbon nanofibers, the as-synthesized CoFe2O4@N-CNF nanohybrid manifests superior OER performance with a low overpotential, a large current density, a small Tafel slope, and long-term durability in alkaline solution, outperforming the single component counterparts (pure CoFe2O4 and N-doped carbon nanofibers) and the commercial RuO2 catalyst.
Impressively, the overpotential of CoFe2O4@N-CNFs at the current density of 30.0 mA cm-2 negatively shifts 186 mV as compared with the commercial RuO2catalyst and the current density of the CoFe2O4@N-CNFs at 1.8 V is almost 3.4 times of that on RuO2 benchmark.
“The electrocatalyst CoFe2O4@N-CNFs features low costs, easy approaches and excellent functions which is easy to make mass production. Therefore, we believe that there is a potential application value of this newly made electrocatalyst in green energy conversion devices (such as metal - air batteries and fuel cells).”Lin Xu added.
“The present work would open a new avenue for the exploration of cost-effective and efficient OER electrocatalyst to substitute noble metals for various renewable energy conversion/storage applications.”Tongfei Li added.
This work was financially supported by the National Natural Science Foundation of China and the Natural Science Foundation of Jiangsu Higher Education Institutions of China.