US EPA

7856326 

Journal Article 

Electrodeposited nanostructured flakes of cobalt, manganese and nickel-based sulfide (CoMnNiS) for electrocatalytic alkaline oxygen evolution reaction (OER) 

Verma, M; Sinha, L; Shirage, PM 

2021 

Yes 

Journal of Materials Science: Materials in Electronics
ISSN: 0957-4522
EISSN: 1573-482X 

32 

9 

12292-12307 

10.1007/s10854-021-05860-3 

WOS:000641681500001 

The nanostructured flakes of cobalt, manganese, nickel-based sulfide (CoMnNiS) were synthesized by facile electrodeposition technique on Ni foam, for electrocatalytic water splitting. Growth of interconnected flake-like, surface morphology of CoMnNiS was evaluated from field emission scanning electron microscopy (FE-SEM), and its formation has been corelated to metal ion denudated layer (MIDL) theory. Electrocatalytic activities, oxygen/hydrogen evolution were tested in 1 M KOH electrolyte. Oxygen evolution reaction (OER) results revealed a Tafel slope of 48 mV/dec, and overpotential of 371 mV@10 mA/cm(2) with an exchange current density of 0.33 mA/cm(2) (from geometrical surface area). On the contrary, hydrogen evolution reaction (HER) activity exhibited a Tafel slope of 101 mV/dec, and overpotential of - 226 mV@10 mA/cm(2) with an exchange current density of 0.13 mA/cm(2). Stability of CoMnNiS electrocatalyst was tested for 21 h. duration, which demonstrates an efficiency of 48 and 56% for OER and HER process, respectively. These electrocatalytic results are attributed to the presence of electrochemical species (multiple oxidation states of Co, Mn, i.e., Co+3/Co+2, and Mn+2/Mn+3/Mn+4) on the sample surface, as evidenced from X-ray photoelectron spectroscopy (XPS). Thus, the electrodeposited CoMnNiS nanostructure proves to be an effective electrocatalyst in alkaline reaction for OER due to its ease of synthesis, performance, and stability.