Exploiting Differential Electrochemical Stripping Behaviors of Fe₃O₄Nanocrystals toward Heavy Metal Ions by Crystal Cutting

Abstract

This study attempts to understand the intrinsic impact of different morphologies of nanocrystals on their electrochemical stripping behaviors toward heavy metal ions. Two differently shaped Fe3O4 nanocrystals, i.e., (100)-bound cubic and (111)-bound octahedral, have been synthesized for the experiments. Electrochemical results indicate that Fe3O4 nanocrystals with different shapes show different stripping behaviors toward heavy metal ions. Octahedral Fe3O4 nanocrystals show better electrochemical sensing performances toward the investigated heavy metal ions such as Zn(II), Cd(II), Pb(II), Cu(II), and Hg(II), in comparison with cubic ones. Specifically, Pb(II) is found to have the best stripping performance on both the (100) and (111) facets. To clarify these phenomena, adsorption abilities of as-prepared Fe3O4 nanocrystals have been investigated toward heavy metal ions. Most importantly, combined with theoretical calculations, their different electrochemical stripping behaviors in view of facet effects have been further studied and enclosed at the level of molecular/atom. Finally, as a trial to find a disposable platform completely free from noble metals, the potential application of the Fe3O4 nanocrystals for electrochemical detection of As(III) in drinking water is demonstrated.

The crystal facet-dependent electrochemical performance of TiO2 nanocrystals for heavy metal detection: Theoretical prediction and experimental proof

“…Currently, anodic stripping voltammetry has been popularly applied to detect heavy metal ions in water owing to its high sensitivity, accurateness, and low cost [4][5][6][7]. To obtain high sensitivity and selectivity, nanostructured metal oxides have been widely employed as modifiers of the working electrodes [8][9][10][11]. The detection strategy stems from the selective adsorption properties of modifiers [12].…”

“…To date, crystal plane effects have gained great interest in lots of fields, such as photocatalysts [19][20], solar cell [21,22], electrochemical energy storage [23,24], and so on. However, to the best of our knowledge, only a few studies have been focused on the facet-dependent electrochemical performances toward heavy metal ions detection [7,9,[25][26][27]. For instance, Xin-jiu Huang research group found that Cu2O microcrystals with different facets showed different sensitivity in the determination of lead ions, following the sequence (111) > (100) > (110) [25].…”

“…For instance, Xin-jiu Huang research group found that Cu2O microcrystals with different facets showed different sensitivity in the determination of lead ions, following the sequence (111) > (100) > (110) [25]. Furthermore, facet-dependent electrochemical behaviors were also observed on other metal oxides, like, SnO2 [26], Fe3O4 [9], and Fe2O3 [27]. Although experimental studies have been demonstrated the effect of crystal facets on the detection of heavy metal ions, the atomistic understanding of the mechanism of the electroanalytical behaviors is far from satisfactory.…”

Electrochemical Detection of Nitrite in Food Based on Poly (3,4-ethylenedioxythiophene) Doped with Fe3O4 Nanoparticles Loaded Carboxylated Nanocrystalline Cellulose

“…18 As an important magnetic nanomaterial, Fe 3 O 4 magnetic nanoparticle received much attention and extensive investigation in the past years for its excellent electrocatalytic activity, biocompatibility and absorption ability. [19][20][21][22][23] For example, a sensitive electrochemical biosensor for the detection of H 2 O 2 from living cells has been developed based on graphene blended with Fe 3 O 4 nanoparticles. 24 Fe 3 O 4 nanosphere decorated with Au nanoparticles was used as a kind of catalyst for the detection of As(III) in water.…”

Enhanced Electrochemical Sensing with Carbon Nanotubes Modified with Bismuth and Magnetic Nanoparticles in a Lab‐on‐a‐Chip

“…Iron oxide coated glassy carbon electrode has also been demonstrated for ultrasensitive detection of heavy metals including Zn II ,C d II ,C u II ,H g II ,a nd Pb II ions. [18,19] Other research attributed the electrochemical performance of Fe 2 O 3 in the detection of Pb ion to be dependent on the facet of the Fe 2 O 3 nanostructure, particularly the facets {012}, {001}, and {110} of the nanocube, nanorod, and nanoplates structures. [20] Further studies focusedo ns ynthesizing Fe 2 O 3 with these effectivef acets exposed for the demonstration of detection of As III .…”