Mixed Valent, Distorted Cobalt Ludwigite (Co₃BO₅/Co₃O₂BO₃) and Its Composite with Reduced Multiwalled Carbon Nanotubes (R‐MWCNT) in Enhancing the Domain Edge‐Sharing Oxygen as Superior Water Oxidation Electrocatalysts

Abstract

Abstract Herein, we report, a hybrid of mixed valent cobalt ludwigite (Co 3 BO 5 ) and reduced‐multiwalled carbon nanotubes (R‐MWCNTs) as an outstanding oxygen evolution reaction (OER) electrocatalyst. Interestingly, the composite acts as a potential OER electrocatalyst, displaying a low overpotential of 270 mV @10 mA cm −2 , which is lower than that for the state‐of‐the‐art RuO 2 catalyst. The remarkable OER performance of the cobalt‐ludwigite is attributed to its basic distorted open crystal structure, which has a relatively high crystal volume, owing to a domain network consisting of edge‐sharing octahedra. Moreover, X‐ray photoelectron spectroscopy clarifies the hybrid of cobalt‐ludwigite and R‐MWCNTs, exhibiting a stable π‐cation‐like interaction between the Co 3+ of Co 3 BO 5 rather than Co 2+ and neutral π‐ cloud of R‐MWCNTs, which helps in enhancing the conductivity of the system. Thus, the overall performance of the composite stems from the basic crystal structure of the Co 3 BO 5 and the existence of synergistic effects between the R‐MWCNTs on Co 3 BO 5 through π‐cation‐like interaction. Hence, the results of this study might be useful in developing more efficient other ludwigite–carbon OER electrocatalysts as affordable alternatives.