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

摘要

To prepare the novel plate-like nanocomposite CoIIITMPyP/Nb3O8, the cationic cobalt (III) tetrakis-5, 10, 15, 20-(N-methyl-4pyridyl) porphyrin ((CoTMPyP)-T-III) was intercalated into the interlayer of the perovskite structural material KNb3O8 via the electrostatic self-assembly of the positively charged CoIIITMPyPmolecules and the electronegative Nb3O8- nanosheets. The Nb3O8- nanosheetswas obtained by exfoliating the protonated product of niobate KNb3O8 in the tetrabutyl ammonium hydroxide (TBAthornOH(-)) aqueous solution. The zeta potential was measured to indicate the stability and uniformity of the Nb3O8 nanosheet colloidal dispersion, and the structure and component of the parent material KNb3O8, the acidified product HNb3O8, and the interlayered nanocomposite (CoTMPyP)-T-III/Nb3O8 were characterized usingXRD, FT-IR, SEMandAFM. Furthermore, the electrocatalytic activity toward the oxygen reduction reaction (ORR) of (CoTMPyP)-T-III/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 -0.723V to -0.300V. The linear correlation of the reduction peak current and the square root of the scan rate suggested a diffusion controlled process.