Electrostatic self-assembly of exfoliated niobate nanosheets (Nb3O8−) and cobalt porphyrins (CoIIITMPyP) utilized for rapid construction of intercalated nanocomposite and exploration of electrocatalysis towards oxygen reduction

Abstract

To prepare the novel plate-like nanocomposite CoIIITMPyP/Nb3O8, the cationic cobalt (III) tetrakis–5, 10, 15, 20–(N–methyl–4–pyridyl) porphyrin (CoIIITMPyP) was intercalated into the interlayer of the perovskite structural material KNb3O8 via the electrostatic self-assembly of the positively charged CoIIITMPyP molecules and the electronegative Nb3O[Formula: see text] nanosheets. The Nb3O[Formula: see text] nanosheets was obtained by exfoliating the protonated product of niobate KNb3O8 in the tetrabutyl ammonium hydroxide (TBA[Formula: see text]OH[Formula: see text]) aqueous solution. The zeta potential was measured to indicate the stability and uniformity of the Nb3O[Formula: see text] nanosheet colloidal dispersion, and the structure and component of the parent material KNb3O8, the acidified product HNb3O8, and the interlayered nanocomposite CoIIITMPyP/Nb3O8 were characterized using XRD, FT-IR, SEM and AFM. Furthermore, the electrocatalytic activity toward the oxygen reduction reaction (ORR) of CoIIITMPyP/Nb3O8 hybrids modified GCE was investigated by the cyclic voltammetry (CV) measurements. The modified GCE exhibited good electrocatalytic activity toward ORR in consideration of the peak shift from [Formula: see text]0.723[Formula: see text]V to [Formula: see text]0.300[Formula: see text]V. The linear correlation of the reduction peak current and the square root of the scan rate suggested a diffusion controlled process.