Amorphous CoFeBO nanoparticles as highly active electrocatalysts for efficient water oxidation reaction

Abstract

The precise control of designing and synthesizing highly efficient water oxidation catalysts is a key role in enhancing the electrochemical processes such as water electrolysis. Herein, we fabricate the ultrafine Fe (variations on Fe amounts, χFe = MFe/M(Co+Fe)) and B-modulated CoFeBO nanoparticles as efficient water oxidation precatalysts. In view of intrinsic amorphous nanostructure, optimal Fe-doping amounts and borate-rich CoFeOOH active nanosheets formed on the surface of CoFeBO nanoparticles during oxygen evolution reaction (OER) process, the CoFeBO (χFe = 0.3) precatalyst has demonstrated active electrochemical water oxidation properties under widen pH value from neutral to alkaline conditions. It exhibits only 263 mV in overpotential to reach a current density of 10 mA/cm2 on glassy carbon (GC) electrode with the lowest Tafel slope of 39 mV/dec in 1 M KOH solution, which outperforms those of individual CoBO and FeBO as well as commercial RuO2 electrocatalyst in the same electrolyte. Moreover, continuous stability tests in 1 M KOH solution by recording potential response at 10 mA/cm2 for 28 h and current response at overpotential of 270 mV for another 28 h show no obvious fluctuation. Combining the merits of cost-efficient, scalable synthesis and active water oxidation performances, amorphous CoFeBO nanoparticles could be employed as highly active OER precatalysts for OER.