Fe/Co‐based Bimetallic MOF‐derived Co₃Fe₇@NCNTFs Bifunctional Electrocatalyst for High‐Efficiency Overall Water Splitting

Abstract

Electrocatalytic water splitting to produce hydrogen and oxygen is regarded as one of the most promising methods to generate clean and sustainable energy for replacing fossil fuels. However, the design and development of an efficient bifunctional catalyst for simultaneous generation of hydrogen and oxygen remains extremely challenging yet is critical for the practical implementation of water electrolysis. Here, we report a facile method to fabricate novel N-doped carbon nanotube frameworks (NCNTFs) by the pyrolysis of a bimetallic metal organic framework (MIL-88-Fe/Co). The resultant electrocatalyst, Co 3 Fe 7 @NCNTFs, exhibits excellent oxygen evolution reaction (OER) activity, achieving 10 mA/cm 2 at a low overpotential of just 264 mV in 1 M KOH solution, and 197 mV for the hydrogen evolution reaction. The high electrocatalytic activity arises from the synergistic effect between the chemistry of the Co 3 Fe 7 and the NCNTs coupled to the novel framework structure. The remarkable electrocatalytic performance of our bifunctional electrocatalyst provides a promising pathway to highperformance overall water splitting and electrochemical energy devices.[a] Q.

Nanostructured Fe-N-C as Bifunctional Catalysts for Oxygen Reduction and Hydrogen Evolution

“…Metal sulfides are also considered as promising electrocatalysts due to its unique properties, high conductivity, high catalytic activity, high affinity for hydrogen adsorption, low cost, and availability [33][34][35]. In addition, M-N-C materials have received recent attention as catalysts for HER [36][37][38]. Tailoring texture of M-N-C materials can boost ORR and HER activity and mass transfer [39][40][41][42].…”

Recent advancements in MOF‐ based catalysts for applications in electrochemical and photoelectrochemical water splitting: A review

“…Yuan et al employed bimetallic MOF (MIL‐88‐Fe/Co) to synthesize a bifunctional catalyst for simultaneous OER and HER. Pyrolysis of MIL‐88‐Fe/Co resulted in N‐doped CNT frameworks with in situ‐reduced metallic Co 3 Fe 7 nanoparticles (Co 3 Fe 7 /NCNTFs) 130 . Yang et al developed an efficient 3D electrode with capabilities to catalyze both OER and HER in alkaline medium via electrodeposition of vertical‐grown 2D Co(OH) 2 nanosheets coupled with 3D ZIF‐67 polyhedra on Ni foam.…”

“…Pyrolysis of MIL-88-Fe/Co resulted in N-doped CNT frameworks with in situ-reduced metallic Co 3 Fe 7 nanoparticles (Co 3 Fe 7 /NCNTFs). 130 Yang et al developed an efficient 3D electrode with capabilities to catalyze both OER and HER in alkaline medium via electrodeposition of vertical-grown 2D Co(OH) 2 nanosheets coupled with 3D ZIF-67 polyhedra on Ni foam. Process of catalytic pyrolysis with the induction of melamine as both nitrogen source and facilitator of CNTs growth to achieve the composites consisting of cobalt nanoparticles confined in multiwall N-CNTs (Co/N-CNT) as depicted in Figure 11.…”

“…These catalysts exhibited high durability, remarkable conductivity, and robust 3D framework structure as they achieved OER overpotential of 264 mV and HER overpotential of 197 mV at 10 mA/cm 2 . Synergistic effect existing between Co3Fe7 and the NCNTs along with novel framework structure is accountable for enhanced performance 130 …”

“…Synergistic effect existing between Co3Fe7 and the NCNTs along with novel framework structure is accountable for enhanced performance. 130 An efficient 3D electrode with capabilities to catalyze both HER and OER in alkaline medium was developed by Yang et al Synthesized electrode showed remarkable electrochemical performance as it required only 1.58 V to achieve 30 mA/cm 2 in an alkali-electrolyzer and the corresponding Tafel slope of 84 mV/dec was observed. This improved performance is due to the unique 3D hierarchical tubular structure and the synergistic effects resulting in increased accessible active sites, accelerateddiffusion of electron/electrolyte, and improved electrical conductivity, hydrophilicity and structural stability of the catalyst.…”