Highly sensitive detection of trace Hg2+ via PdNPs/g-C3N4 nanosheet-modified electrodes using DPV

Abstract

In this work, Pd nanoparticle (PdNP)-modified graphite carbon nitride (g-C3N4) porous nanosheets (PdNPs/g-C3N4) were synthesized via reduction by hydrazine hydrate. The morphology analysis of the PdNPs/g-C3N4 nanosheets indicated that PdNPs were uniformly distributed on the g-C3N4 surface. The PdNPs/g-C3N4 modified glassy carbon (GC) electrode (PdNPs/g-C3N4/GC) was used for the trace detection of Hg2+ by differential pulse voltammetry (DPV). Excellent sensitivity and selectivity toward the determination of trace Hg2+ were achieved, as well as excellent anti-interference, repeatability, and long term stability under similar optimal experimental conditions. The limit of detection (LOD) for Hg2+ was 0.009 µg/L, lower than WHO standard (1.0 µg/L) and previously reported values. Moreover, the PdNPs/g-C3N4/GC electrode was employed to detect Hg2+ ions in real water environments, including local tap, lake, and river water samples, aiming at manifesting the potential practical applications of the electrode. The outstanding electrochemical performance of the PdNPs/g-C3N4 GC electrode toward Hg2+ detection was mainly ascribed to the combined advantages of the large specific surface area of the nanosheets and improved electrical conductivity owing to the deposited PdNPs. The current study provides a green and feasible method for the detection of trace Hg2+ in real water environments.