A Facile Synthesis of FeCo Nanoparticles Encapsulated in Hierarchical N‐Doped Carbon Nanotube/Nanofiber Hybrids for Overall Water Splitting

Abstract

Development of efficient and cost-effective transition metalbased catalysts for overall water splitting is desired. Herein, a facile synthesis procedure for the development of FeCo bimetallic alloy nanoparticles (NPs) located on the tips of multiwalled carbon nanotubes (CNTs) supported over N-doped carbon nanofibers (CNFs) is presented. The CNTs, not only prevent FeCo NPs from agglomeration by encapsulating them at the tip but also provide an efficient electron pathway. The materials exhibited excellent performance in oxygen evolution reaction (OER) and decent activity in hydrogen evolution reaction (HER) with long-term durability of up to 48 hours on glassy carbon electrode. The best OER activity with a overpotential of 283 mV@10 mAcm À 2 and Tafel slope of 38 mV/dec was achieved with a hierarchically porous catalyst having Fe : Co molar ratio of 1 : 2. This synthesis approach is promising for growing well-dispersed CNTs over N-doped carbonaceous support using bimetallic alloys for electrocatalytic applications.catalyst's intrinsic resistance and facilitating the charge transfer between catalyst and the electrolyte interface. This work might introduce a new and cost effective way for the homogenously distributed in-situ growth of CNTs over N doped carbonaceous support that have potential applications as electrocatalyst in metal air batteries, water splitting and fuel cells.

Super-Hydrophilic Hierarchical Ni-Foam-Graphene-Carbon Nanotubes-Ni2P–CuP2 Nano-Architecture as Efficient Electrocatalyst for Overall Water Splitting

“…Over the last few decades, the transition-metal-based oxide/hydroxides, sulfides, selenides, phosphide, bimetallic alloy, etc ., have had massive attention in the field of electrochemistry for overall water splitting. , Among them, earth-abundant transition metal phosphides (TMPs) have shown the best catalytic activity due to the presence of the multielectron orbitals of phosphorus, , good electrical conductivity, ,, moderate binding energy with hydrogen (H) in the different reaction medium, and the “ensemble effect” (where negatively charged P weakens the M–H bond and promotes a faster H 2 desorption rate). Different morphologies of TMPs have been investigated for high catalytical performance toward HER, OER, and overall water splitting, such as hollow nanoparticles-Ni 2 P, disk-like Ni 5 P 4 , nanowire array-Cu 3 P, CoP, nanosheet-MoP 2 , hollow nanosphere-MoP, nanotube-CoP, microsphere-FeP, etc .…”

“…However, most of these bimetallic phosphides have been synthesized via metal oxide or hydroxide precursors, leading to the formation of multiphase agglomeration and the reduction of electroactive sites, which in-turn drop in electrical conductivity as well as weaken the electrochemical activity . Thus, researchers are following an alternate path to grow the bimetallic phosphides on conducting substrates like graphene, carbon nanotubes (CNTs), carbon cloth, carbon fiber, Ni-foam, and Cu-foam to improve the overall conductivity and to avoid agglomeration in a faster electrons transfer process . The porous architecture of carbonaceous matrix coated with electrodeposited active materials imparts an advantageous hydrophilicity as well as an aerophobic surface commonly observed to create a low-ohmic-resistive path at the electrode–electrolyte interface.…”

Poly(3‐hexylthiophene) stabilized ultrafine nickel oxide nanoparticles as superior electrocatalyst for oxygen evolution reaction: Catalyst design through synergistic combination of π‐conjugated polymers and metal‐based nanoparticles

“…It is worthwhile mentioning here that the catalytic activity of P3HT@NiO hybrid NPs even exceeds the state of art RuO 2 at high current densities as it requires only 310 mV overpotential to achieve a current density of 10 mA cm À2 with low Tafel slope (74 mV dec À1 ) than RuO 2 that takes 400 mV overpotential with Tafel slope (105 mV dec À1 ). 68 These results suggest that the P3HT@NiO NPs (1:1 molar ratio) based catalyst improved the sluggish kinetics of OER reaction by facilitating the four-electron transfer process. Furthermore, the Tafel slope value of P3HT@NiO NPs (1:1 molar ratio) catalyst (74 mV dec À1 ) validated the simultaneous four-electron transfer process in OER of water splitting process (Figure 5d).…”

“…Due to the relatively higher number of active sites available on the surface of well dispersed small size NPs, they exhibited lower onset potential and higher catalytic efficiency compared to other materials produced in this study. It is worthwhile mentioning here that the catalytic activity of P3HT@NiO hybrid NPs even exceeds the state of art RuO 2 at high current densities as it requires only 310 mV overpotential to achieve a current density of 10 mA cm −2 with low Tafel slope (74 mV dec −1 ) than RuO 2 that takes 400 mV overpotential with Tafel slope (105 mV dec −1 ) 68 . These results suggest that the P3HT@NiO NPs (1:1 molar ratio) based catalyst improved the sluggish kinetics of OER reaction by facilitating the four‐electron transfer process.…”

Facile preparation and highly efficient sorption of magnetic composite graphene oxide/Fe3O4/GC for uranium removal

“…Nowadays, carbonaceous materials, such as activated carbon 1 , carbon nanotubes 2 , carbon fibre 3 , and mesoporous carbon 4 , have been widely applied due to their availability, acid–base stability, and thermal resistance. These carbonaceous materials generally are fabricated via high temperature reaction 5 , pyrolysis 6 – 8 , gasfication 9 , electrospinning technique 10 , etc. Amongst these techniques, hydrothermal carbonization (HTC) has become a proficient synthesis technique owing to its cheapness, simplification, mild reaction conditions, and lack of any organic solvent and toxic waste.…”