Rational synthesis of alkaline earth metal vanadates: Structural origin of MgVO3 honeycomb lattice system and its electrochemical analysis for the detection of sulfadiazine

Abstract

In this study, well-defined alkaline earth metal vanadates, including MgV, CaV, SrV, and BaV, are synthesized using a simple hydrothermal method, and the crystalline structure, morphology, and structural parameters of the synthesized alkaline earth metal vanadates are investigated and compared. Among the alkaline earth metal vanadates, the MgV shows the unique 3D architecture and MgVO3 hexagonal phase with space group R-3c (167) and a single crystalline phase in V4+ valence state and Mg2+ state revealing cation dimerization in 3d1 honeycomb system. Further Raman spectroscopy with Lorentzian peak fitting and X-ray photoelectron spectroscopy exhibit the phase development with a bucky-ball structure. In order to apply the unique feature, the MgV based composite with reduced graphene oxide as a co-catalyst is prepared to examine the practical application for electrochemical sensing of sulfadiazine. The differential pulse voltammetry and the amperometry i-t analysis demonstrate the superior performance of MgV/reduced graphene oxide composite for the sulfadiazine detection including a superior low limit of detection of 9 nM from the differential pulse voltammetry measurements and 3 nM from the amperometry i-t analysis as well as excellent selectivity and long-term stability. These results are attributed to the enhanced electron transfer and ion diffusion from the synergistic effect of unique MgV and reduced graphene oxide. Moreover, the MgV/reduced graphene oxide composite delivers excellent capability in the detection of sulfadiazine in real samples of human blood serum, industrial wastewater, and pharmaceutical tablet.