Well-matched core-shell NiO@LaMnO3/MWCNTs p-p homotype heterojunction for ascorbic acid detection

A novel core-shell p-p homotype heterojunction based on NiO@LaMnO3 and multi-walled carbon nanotubes (NiO@LaMnO3/MWCNTs) has been designed and synthesized via electrostatic self-assembly method. The phase compositions and morphology were verified by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM). A series of electrochemical tests showed that NiO@LaMnO3/MWCNTs modified electrode had a magnifying effect on the electrochemical response signal of ascorbic acid (AA) detection. The current response is linearly increased in the range of 2.60-36.44 mu mol/ L with the linear regression equation being I(mu A) = 0.5902C (mu mol/L) + 1.4407 (R2 = 0.9909), and the detec-tion limit (S/N = 3) being 2.41 mu mol/L. Moreover, NiO@LaMnO3/MWCNTs/GCE electrochemical sensor pre-sented satisfying selectivity, stability, repeatability, and can be used to analyze the AA concentration in real daily drinks. The relatively excellent electrocatalytic activity should be attributed to high electroactive surface area, well-matched core-shell structure and synergetic effect of p-p homotype heterojunction. This work offer applicable guidelines for the design of core-shell p-p heterojunction electrode materials for the application of electrochemical sensor.

Automated summary

A novel core-shell p-p homotype heterojunction of NiO@LaMnO3 and multi-walled carbon nanotubes (NiO@LaMnO3/MWCNTs) was synthesized via electrostatic self-assembly. The composition and morphology were confirmed using XRD, SEM, and TEM. The modified electrode showed enhanced electrochemical response for ascorbic acid (AA) detection, with a linear current response in the range of 2.60-36.44 μmol/L and a detection limit of 2.41 μmol/L. The NiO@LaMnO3/MWCNTs/GCE sensor exhibited excellent selectivity, stability, repeatability, and could be used for AA analysis in real daily drinks. The high electrocatalytic activity was attributed to the large electroactive surface area, well-matched core-shell structure, and synergistic effect of the p-p homotype heterojunction.