Electrostatic self-assembly behaviour of exfoliated Sr2Nb3O10 (-) nanosheets and cobalt porphyrins: exploration of non-noble electro-catalysts towards hydrazine hydrate oxidation

In our research, a convenient exfoliation/restacking route was used to fabricate a sandwich-structured nanocomposite of Sr2Nb3O10/CoTMPyP [5,10,15,20-tetrakis(N-methylpyridinium-4-yl)porphyrinato cobalt] via electrostatic interaction between colloidal dispersion and cobalt porphyrin aqueous solution. The final self-assembled products were characterized by XRD, FTIR, UV–Vis, SEM, TEM, AFM, and ICP. During the exfoliation procedure, the well-dispersed Sr2Nb3O10− colloidal dispersion was obtained with the zeta potential value of − 44.2 mV. Additionally, the existence of unilamellar Sr2Nb3O10− nanosheet was evidenced by AFM, and zeta potential values of the reassembly process with the addition of CoTMPyP aqueous solution into the colloidal dispersion were measured by a Zetasizer Nano apparatus. Above all, the final Sr2Nb3O10/CoTMPyP hybrid film displayed excellent electro-catalytic activities towards hydrazine hydrate oxidation with peak potential at 0.158 V in pH 7.0 PBS indicated by CV measurements; moreover, a detection limit of 3.52 × 10−5 M was obtained in the concentration range of 5 × 10−5–9.9 × 10−4 M at a signal-to-noise ratio of 3.0.