(175c) A Facile Synthesis of FeCo Nanoparticles Encapsulated in Hierarchical N-Doped Carbon Nanotube/Nanofiber Hybrids for Overall Water Splitting

Electrochemical water splitting for the production of hydrogen is considered as an important reaction for the renewable energy technology which requires the development of highly efficient and cost effective catalysts. In this work, a facile synthesis protocol for the development of FeCo bimetallic alloy nanoparticles (NPs) supported over multi-walled carbon nanotubes (CNTs) and carbon nanofibers is presented. The CNTs, not only prevent FeCo NPs from agglomeration by encapsulating them in their hard protective shell at the tip but also provide an efficient electron pathway. Impressively, based on the synergistic effect of highly conductive and homogeneously distributed CNTs and FeCo NPs over N-doped carbon nanofiber support (FeCo@CNT/NCNF), the material exhibited excellent performance in oxygen evolution reaction (OER) and decent activity in hydrogen evolution reaction (HER) with exceptional durability of 48 hours even on glassy carbon electrode. By optimizing the FeCo precursors dosage it is deduced that FeCo@CNT/NCNF with Fe:Co ratio of 1:2 showed best activity in OER, with 283 mV overpotential required to achieve 10 mAcm^-2 and very low Tafel slope of 38mV/dec, which is better than most reported studies for similar materials. The Faradic efficiency of OER and HER was also tested by using water displacement method and it was found close to 99 %. This simple and cost-effective synthesis approach is very promising for growing well-dispersed CNTs over N-doped carbonaceous support using bimetallic transition metal alloys for applications in renewable energy technologies, batteries, sensors, etc.