Identifying Phase‐Dependent Electrochemical Stripping Performance of FeOOH Nanorod: Evidence from Kinetic Simulation and Analyte–Material Interactions

Abstract

Metal hydroxide nanomaterials are widely applied in the energy and environment fields. The electrochemical performance of such materials is strongly dependent on their crystal phases. However, as there are always multiple factors relating to the phase‐dependent electrochemistry, it is still difficult to identify the determining one. The well‐defined crystal phases of α‐ and β‐FeOOH nanorods are characterized through the transmission electron microscopy by a series of rotation toward one rod, where the cross‐section shape and the growth direction along the [001] crystalline are first verified for 1D FeOOH nanostructures. The electrosensitivity of the two materials toward Pb(II) is tested, where α‐FeOOH performs an outstanding sensitivity whilst it is only modest for β‐FeOOH. Experiments via Fourier transform infrared spectroscopy, X‐ray absorption fine structure (XAFS), etc., show that α‐FeOOH presents a larger Pb(II) adsorption capacity due to more surficial hydroxyl groups and weaker PbO bond strength. The reaction kinetics are simulated and the adsorption capacity is found to be the determining factor for the distinct Pb(II) sensitivities. Combining experiment with simulation, this work reveals the physical insights of the phase‐dependent electrochemistry for FeOOH and provides guidelines for the functional application of metal hydroxide nanomaterials.

ZnFe2O4 Nanoparticles for Electrochemical Determination of Trace Hg(II), Pb(II), Cu(II), and Glucose

“…As depicted in Figure b, the dissolution peak currents are closely associated with Hg­(II) concentration in the range from 0.1 to 1.0 μM, and in detail, the linear equation is expressed as follows: y = 24.61 x (μM) + 2.69 ( R 2 = 0.998). Therefore, the sensitivity and limit of detection (LOD, S/N = 3) are supposed to be 24.61 μA μM –1 and 1.61 nM. Furthermore, the electrochemical detection of Pb­(II) and Cu­(II) shows good detection performance under the same conditions, and the corresponding DPASV curves are shown in Figure c,d, for which the linear equation can be expressed as y = 14.75 x (μM) + 1.36 ( R 2 = 0.988) and y = 8.22 x (μM) + 2.31 ( R 2 = 0.998), respectively (Figure c,d).…”

“…49 Therefore, in the simultaneous determination process, the surface of the ZFO/GCE first forms Hg film and the Cu−Hg intermetallic compound, which can improve the sensitivity to Cu(II). 50,51 The enhanced electrochemical response of ZFO-modified electrode materials for HMIs may come from the following effects: 40,41 (1) because of the small size of ZFO nanoparticles, numerous adsorption sites are exposed on the surface of nanoparticles, which is beneficial to the adsorption of Pb(II), Cu(II), and Hg(II); (2) the obtained ZFO nanoparticles have a large surface area and more mesopores, which not only provides a mass transfer channel for electrolyte ions but also helps to improve their electrochemical activity; (3) HMIs have high stripping efficiency on the ZFO surface and can be successfully stripped from the ZFO/GCE surface to the electrolyte, which shows a larger peeling peak current.…”

Tuning Iron–Oxygen Covalency in Perovskite Oxides for Efficient Electrochemical Sensing

“…Notably, the LaFeO 3 aerogel shows the highest detection sensitivity and lowest LOD when comparing with the recently reported results (Figures b and S16 and Table S5). − Both the theoretical and practical LODs of the LaFeO 3 aerogel are much lower than the tolerance value (48 nM) in the drinking water set by the World Health Organization.…”

Highly Selective Photocatalytic Conversion of Carbon Dioxide by Water over Al-SrTiO3 Photocatalyst Modified with Silver–Metal Dual Cocatalysts

“…The Ag K-edge and Fe K-edge X-ray absorption spectra were analyzed using the beamline BL01B1 of SPring-8 (Japan Synchrotron Radiation Research Institute, Hyogo, Japan). The compounds α-FeOOH and β-FeOOH were synthesized in-house according to a previously reported method, 46 as described in the Supporting Information. All reference sample measurements were performed in the transmission mode.…”

“…Particularly, Fe-based materials offer a new opportunity to develop efficient, economical, and eco-friendly photocatalysts for the photocatalytic conversion of CO 2 by H 2 O because of the abundance, nontoxicity, and high photo and heat stabilities of this group VIII metal. Particularly, α-Fe 2 O 3 has been reported as a photocatalyst for water oxidation under visible-light photoirradiation. − In addition, studies of iron oxyhydroxide (FeOOH) as a material for catalytic water splitting are on the rise because of its capability in improving O 2 evolution. , Moreover, very recently, FeOOH was reported as an effective and durable cocatalyst for photocatalytic and electrocatalytic overall water splitting under visible light irradiation. − However, to date, this compound has rarely been studied in the photocatalytic conversion of CO 2 . With this in mind, in this study, we investigated the effect of the Fe cocatalyst on the photocatalytic properties of Ag–Fe/Al-SrTiO 3 for the photocatalytic conversion of CO 2 by H 2 O under photoirradiation.…”