Green dodecylamine-capped hafnium oxide nanosystem: evaluating the toxicity profile and electrochemical hydrogen sulfide sensing efficiency

Abstract

This research, for the first time, reports the fabrication of dodecylamine-capped hafnium oxide nanomaterial (DDA@HfO₂ NM) onto gold (Au) electrodes for the highly selective and sensitive detection of sulfide (HS⁻) electrochemically. A facile, green, and economic two-step hydrothermal optimized approach was followed to synthesize monocrystalline nanospheres of DDA@HfO₂ NM (20–30 nm) and supported through theoretical calculations carried using Gaussian 03 series version. The electrochemical investigations and spectroscopic analysis revealed the interaction of DDA through an electron rich site (amine group) with additional binding surface-active sites on HfO₂. DDA provided better stability and charge density to modulate the electrical conductivity of the NMs and further derived the selective detection of HS⁻. Moreover, electrostatic attraction-based interactions between the dipole of HS⁻ and the ionic field developed by charges in an oxide may play a supportive role in the selective adsorption process. The fabricated sensor exhibits a remarkable, selective, and sensitive electrocatalytic oxidation of HS⁻ (in PBS 7.4) over the DDA@HfO₂/Au nanosystem with varied concentrations of Na₂S using linear sweep voltammetry (LSV). The DDA@HfO₂/Au nanosystem showed a fast electron transfer pathway, exhibited a nanomolar limit of detection (LOD) of 181.42 nM, high sensitivity, and a broad linear dynamic range (LDR) from 1 to 130 μM. The intended method was applied for the determination of sulfide (HS⁻) in the pretreated samples, interference studies, and recovery investigations. In addition, to verify the biocompatibility of the as-fabricated NMs, the antibacterial assay and toxicity profile were also examined.