Benzyltriphenylphosphonium chloride (BTPPC) and halide ions (KI) in 0.3 M phosphoric acid solution were studied by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), at different corrosion inhibitor concentrations and temperatures. Effects on corrosion of mild steel. Temperature dynamics, scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies were performed respectively. Results from potentiodynamic polarization studies indicate that BTPPC and KI are hybrid inhibitors of mild steel in 0.3 M phosphoric acid. The synergistic corrosion inhibition effect of Benzyltriphenylphosphonium chloride  and KI on mild steel in 0.3 M H3PO4 containing low concentrations of I- was evaluated by potentiodynamic polarization studies. Experimental results show that the presence of iodide ions in the solution stabilizes the adsorption of BTPPC molecules on the metal surface and improves the corrosion inhibition efficiency of BTPPC. The corrosion behavior of mild steel in 0.3 M H3PO4 without and with different concentrations of inhibitors was studied in the temperature range (298 to 338) K. Inhibitor efficiency increased with increasing concentration at all temperatures. Inhibition efficiency decreases with increasing temperature. The adsorption of BTPPC + KI followed the Temkin adsorption isotherm. Kinetic and thermodynamic parameters such as effective activation energy (Ea), Gibbs free energy of adsorption (AGo ads), and heat of adsorption (AHoads) indicate that the adsorption of BTPPC + KI on the mild steel surface is mainly physical in nature. The results of scanning electron microscopy and atomic force microscopy are consistent with the electrochemical analysis results.

A novel, cheap, and simple nonenzymatic current sensor was prepared based on the electrodeposition of Mg/Fe layered double hydroxide (Mg/Fe-LDH) on glassy carbon (GC) electrodes. The electrochemically synthesized Mg/Fe-LDH was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and cyclic voltammetry (CV). The prepared Mg/Fe-LDH exhibits excellent electrocatalytic activity for the reduction of 2-nitrophenol (2-NP). The results show that the Mg/Fe-LDH modified electrode can be used as a non-enzymatic current sensor to measure 2-NP in a concentration range of 5-560 μM, with a detection limit of 4 μM. This method is suitable for the determination of 2-nitrophenol in industrial wastewater. Furthermore, the Mg/Fe-LDH modified electrode showed satisfactory reproducibility and long-term stability.