1. High‐Performance Bifunctional Ni−Fe−S Catalyst in situ Synthesized within Graphite Intergranular Nanopores for Overall Water Splitting
- Author
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Jing Li, Chao-Xiong Li, Fang Li, Bing Li, Xin-Ming Yang, Jian-Bo He, and Xiao-Fan Yang
- Subjects
Electrolysis ,Materials science ,Hydrogen ,General Chemical Engineering ,Oxygen evolution ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Catalysis ,chemistry.chemical_compound ,Nickel ,General Energy ,chemistry ,Chemical engineering ,law ,Environmental Chemistry ,Water splitting ,General Materials Science ,Graphite ,0210 nano-technology ,Bifunctional - Abstract
Low-cost and efficient bifunctional catalysts are urgently needed for overall water splitting used in large-scale energy storage. In this study, we develop a nickel and iron (di)sulfide (Ni-Fe-S) composite catalyst that is in situ synthesized and fixed within the intergranular nanopores inside high pure polycrystalline graphite. Two precursor solutions (reactants) may permeate the graphite intergranular pores to a depth of more than 3.5 mm. The nanoscale pores serve as an array of nanoreactors for the synthesis of the Ni-Fe-S nanoparticles under conditions much milder than usual. The prepared catalyst efficiently catalyzes both the hydrogen and oxygen evolution reactions (HER and OER) in 1.0 M KOH. It delivers a current density of 400 mA cm-2 at a full cell voltage of around 2.3 V without considerable activity decay over 24 h electrolysis. The active species of the catalyst are different for the HER and OER and discussed accordingly. The synthesis strategy based on the nanopores in a monolithic conductive substrate proves to be a simple, efficient, and promising way to prepare electrocatalysts that are cheap, abundant, and industrially attractive.
- Published
- 2021