Ionic Liquid-Derived Co₃O₄-N/S-Doped Carbon Catalysts for the Enhanced Water Oxidation

Abstract

The development of cost-effective electrocatalyst with high activity and stability during the oxygen evolution reaction (OER) is a prerequisite for commercialization of several energy storage/generation technologies. Herein, porous carbon materials doped with Co, nitrogen, and sulfur were synthesized through the carbonization of a mixture containing [1-vinylimidazolium] [HSO4] ionic liquid (IL) and CoCl2 under an inert atmosphere. The structural diversity of ionic liquids offered control over the structure and properties of the carbon materials at the molecular level. The protic ionic liquid used acted as a soft template and a source of heteroatoms. A change in the mass ratio of cobalt chloride to ionic liquids resulted in materials with three different morphologies with/without S and N. The resulting Co10-NS-C material exhibited considerably enhanced catalytic performance toward the OER, which compared favorably to that of state-of-the-art Ru-based catalysts. Moreover, the Co10-NS-C catalyst demonstrated excellent stability up to 8 h without any decay in catalytic current.

Critical Review, Recent Updates on Zeolitic Imidazolate Framework‐67 (ZIF‐67) and Its Derivatives for Electrochemical Water Splitting

“…[102] Irrespective of pH of electrolyte under standard temperature and pH, equilibrium potential of water splitting is 1.228 V. [102] Yet, due to slothful kinetics and unfavorable thermodynamics of the HER and OER, in practice, water splitting is always conducted at applied potentials above the thermodynamic potential. [103] Thus, the operating potential (v op ) of a water electrolyzer is given as:…”

“…Irrespective of pH of electrolyte under standard temperature and pH, equilibrium potential of water splitting is 1.228 V. [ 102 ] Yet, due to slothful kinetics and unfavorable thermodynamics of the HER and OER, in practice, water splitting is always conducted at applied potentials above the thermodynamic potential. [ 103 ] Thus, the operating potential ( v op ) of a water electrolyzer is given as: where η is called overpotential and it is defined as the difference between the equilibrium potential of a reaction and the potential at which that reaction occurs in practice. The exact value of η is determined by different factors, including the activation barriers of cathodic and anodic reactions as well as design of the electrochemical cell.…”

Ionic Liquid-Assisted Synthesis of Hierarchical One-Dimensional MoP/NPC for High-Performance Supercapacitor and Electrocatalysis

“…Especially for 1-butyl-3-methylimidazolium-based ILs, it can induce the inorganic nanomaterials to grow into sheet morphology or self-assembly into a hierarchical structure. Compared with an organic solvent or surfactant-assisted system, ILs build up a more direct and facial route for the syntheses of various nanostructured materials. − Moreover, carbon layer coupling can improve the conductivity of the electrode nanomaterial and prevent the structure to collapse. − In addition, the existence of the carbon layer can provide an electric double-layer capacitance. Therefore, if hierarchically structured MoP forms hybrid with the carbon layer, the resultant nanomaterials will exhibit higher electrochemical activity and enhanced stability.…”

Nitrogen- and Sulfur-Doped Carbon Obtained from Direct Hydrothermal Carbonization of Cellulose and Ammonium Sulfate for Supercapacitor Applications

“…11 Chaugule et al also synthesized N-and S-doped porous carbon materials via thermal decomposition of a mixture including VPIL and cobalt chloride under a N 2 atmosphere. 12 However, there is no research to date about the direct synthesis of N-and S-doped carbon materials via an HTC process using inorganic precursors as heteroatom sources.…”

“…However, at present, only organic heteroatom-containing raw materials are used for doping reactions including thiourea as a heteroatom source as well as via pyrolysis of melanosomes . Chaugule et al also synthesized N- and S-doped porous carbon materials via thermal decomposition of a mixture including VPIL and cobalt chloride under a N 2 atmosphere . However, there is no research to date about the direct synthesis of N- and S-doped carbon materials via an HTC process using inorganic precursors as heteroatom sources.…”