Gold nanoparticles decorated three-dimensional porous graphitic carbon nitrides for sensitive anodic stripping voltammetric analysis of trace arsenic(III)

Abstract

A new material of three-dimensional porous graphitic carbon nitride (g-C3N4) decorated by gold nanoparticles (AuNPs) (AuNPs/g-C3N4) was designed using a mesoporous molecular sieve (SBA-15) as the sacrificial template. Cast-coating the as-prepared AuNPs/g-C3N4 on the glassy carbon electrode (GCE) can yield an AuNPs/g-C3N4/GCE for sensitive linear sweep anodic stripping voltammetry (LSASV) analysis of trace As(III). The as-prepared AuNPs/g-C3N4/GCE electrode demonstrates superiorities compared to that of a gold nanoparticles modified GCE (AuNPs/GCE) prepared by electrochemical deposition. These results show the specialties of g-C3N4 for increasing the activity and sensitivity of gold nanoparticles. Under an optimum conditions (400 s preconcentration at −0.45 V in 0.50 M aqueous H2SO4, 5 V s−1), the LSASV peak current for the As(0)-As(III) oxidation responded linearly to As(III) concentration from 0.005–1.00 μM (r2 = 0.992) with an extremely low limit of detection (LOD) of 2.9 nM (0.22 ppb, S/N = 3); meanwhile the peak current for the As(III)–As(V) oxidation was also linear with As(III) concentration from 0.05 to 1.0 μM (r2 = 0.990) with a LOD of 16 nM (1.2 ppb, S/N = 3). More importantly, the feasibility of AuNPs/g-C3N4/GCE for analyzing inorganic As(III) in real water further demonstrates the practicability for our designed electrode.