NiSFeS/N, S co‐doped carbon hybrid: Synergistic effect between NiS and FeS facilitating electrochemical oxygen evolution reaction

Abstract

Summary A series of NiSFeS/N, S co‐doped carbon (NixFeyS/NSC) for electrochemical oxygen evolution reaction (OER) were synthesized by a co‐precipitation method and followed by pyrolysis in N2 atmosphere. NiSFeS hybrid was uniformly integrated with N, S co‐doped carbon in NixFeyS/NSC. NixFeyS/NSC showed high OER catalytic activity, and the optimized Ni60Fe40S/NSC afforded an OER overpotential of ~239 mV to deliver a current density of 10 mA cm−2 and showed a corresponding Tafel slope of ~30.9 mV dec−1 in 1 M KOH. Such OER catalytic activity was not only higher than that of IrO2, but also comparable with that of the most recently reported NiFe‐based sulfides for OER. Further study indicated that hybridizing NiS with FeS resulted in a synergistic effect for OER. The hybridization increased total amount of sulfides as active species, therefore enhancing the OER catalytic activity. In addition, the hybridization benefited the formation of petal‐like morphologies that contributing much to higher electrochemically active surface area (ECSA), and also boosted the content of graphitic and N, S co‐doped carbon that improving charge transfer efficiency.

Synthesis of iron and vanadium co‐doped mesoporous cobalt oxide: An efficient and robust catalysts for electrochemical water oxidation

“…[4][5][6] However, the OER's sluggish reaction kinetics involves a transfer of the four-electron process, and the mechanism is relatively complex, limiting the water electrolysis efficiency. [7][8][9][10][11][12] Consequently, numerous research efforts have been dedicated to designing efficient electrocatalysts to promote or accelerate the OER reactions. To date, no electrode material is capable of reaching the equilibrium potential of 1.23 V RHE , [13][14] which agrees to the minimum energy required for the reaction.…”

“…In alkaline media, the water electrolysis involves the oxygen evolution reaction (OER), a thermodynamically uphill reaction demanding high overpotentials 4‐6 . However, the OER's sluggish reaction kinetics involves a transfer of the four‐electron process, and the mechanism is relatively complex, limiting the water electrolysis efficiency 7‐12 . Consequently, numerous research efforts have been dedicated to designing efficient electrocatalysts to promote or accelerate the OER reactions.…”

Biomass carbon dual‐doped with iron and nitrogen for high‐performance electrocatalyst in water splitting

“…N has the larger electronegativity than carbon, thus can modulate the electronic structure of carbon. 24 The as-obtained electrocatalyst CA (abbreviation of "carbon from amaranth") @Fe(1:3)-800 shows outstanding electrocatalysis performances with the overpotential for OER is 265 mV at 10 mA cm −2 and the Tafel slope is 76.7 mV dec −1 , which are superior to those of commercial RuO 2 . Furthermore, the water splitting voltage of CA@Fe(1:3)-800//CA@Fe(1:3)-800 electrocatalyst system is only 1.53 V at 10 mA cm −2 , which is also lower than commercial RuO 2 //Pt/C system.…”

“…Meanwhile, potassium ferricyanide was used as heteroatom dopant to further activate carbon material, because potassium ferricyanide can replace KOH to realize Fe and N dual‐doping through one‐step way. N has the larger electronegativity than carbon, thus can modulate the electronic structure of carbon 24 . The as‐obtained electrocatalyst CA (abbreviation of “carbon from amaranth”) @Fe(1:3)‐800 shows outstanding electrocatalysis performances with the overpotential for OER is 265 mV at 10 mA cm −2 and the Tafel slope is 76.7 mV dec −1 , which are superior to those of commercial RuO 2 .…”

Highly active bifunctional electrocatalyst: Nanoporous (Ni,Co) 0. 85 Se anchored on rGO for water and hydrazine oxidation

“…This can be due to the fact that OER requires much higher overpotential compared with HER induced by its four electrons oxidation, leading to a high overall voltage in overall water splitting. [5][6][7] Employing active electrocatalysts needed for OER and using the oxidation reaction of ethanol, methanol, benzyl alcohol, urea and hydrazine to substitute OER are two effective methods to reduce the overall cell voltage. 8,9 Among these oxidative processes, the electro-oxidation of hydrazine is one of the most promising candidates because of its low oxidation overpotential and zero carbon emission.…”