Abstract

The development of high-performance electrochemical platforms for quantifying environmental pollutants remains a critical challenge. In this work, we report the strategic tailoring of neodymium doping concentration in lanthanum indate (LaInO3) nanostructures to enhance the electrocatalytic detection of nitrite (NO2-). A series of LaInO3:Nd3+ x% perovskites (x = 1, 3, 5 and 7%) was synthesised via a modified citrate-gel method and systematically characterised. Structural analysis by Le Bail refinement and electron microscopy confirmed the successful incorporation of Nd3+ into the orthorhombic lattice, resulting in morphological changes that optimise the active surface area. Electrochemical studies revealed that the 5% Nd-doped LaInO3 (LaInO3:Nd3+ 5%) modified glassy carbon electrode exhibits superior electrocatalytic activity toward NO2-oxidation compared to its undoped and over-doped counterparts. Under optimised conditions, the sensor demonstrated a wide linear range from 4 to 100 & micro;M, a remarkably low limit of detection (LOD) of 22 nM (LOD=3 sigma/m), and high sensitivity (0.168 mA cm-2 & micro;M-1). Furthermore, the sensor displayed excellent anti-interference capabilities against common ions, as well as outstanding reproducibility and long-term stability. The practical applicability of the proposed method was validated by monitoring NO2-in diverse water matrices (tap and mineral water), yielding recovery rates of 94.0-106.5%. These results position Nd-doped LaInO3 nanostructures as an efficient material for the next electrochemical environmental monitoring devices.