Large Magneto-Current Effect in the Electrochemical Detection of Oxalate in Aqueous Solution

Abstract

Herein, we first report an interesting observation of a large magneto-current (MC) of nearly 30% based on the electrochemical oxidation of oxalate in aqueous solution at room temperature. The large MC is ascribed to spin-dependent oxidation of oxalate. Both singlet and triplet radical pairs are generated during the electrochemical oxidation of oxalate. An applied magnetic field could accelerate the spin evolution of a singlet radical pair into its triplet state. The triplet radical pair has a much larger dissociation probability than the singlet radical pair because of the Pauli exclusion principle. Thus, enhancing the triplet yield could largely increase the oxidation rate of oxalate and generate significant MC. The significant MC effect provides a new approach to study spin evolution of radical pairs in electrochemical cells. Furthermore, an effective analytical method for oxalate determination can be developed based on the significant MC effect.

Magnetic-Field-Induced Electrochemical Performance of a Porous Magnetoplasmonic Ag@Fe3O4 Nanoassembly

“…Here, the Lorentz force ( F L ) is expressed as the cross product of the current density, j (velocity of electrolytes), in the presence of an external magnetic field, and magnetic induction, B , F L results in the convection of the reactive components around the diffusion layer in the liquid solution and increases the transport of reactive species toward the electrode surface, and as a result increasing the rate of reaction at the electrode/electrolyte interface. , This force dominates the inhomogeneous and low-gradient magnetic fields . It has a maximum value when j and B are orthogonal …”

“…14 It has a maximum value when j and B are orthogonal. 16 The potential of the enhancement of mass transport and convection of electrolytes by magnetized NPs was analyzed in the NP layer. To investigate the macroscopic effect of the MagPlas NP-modified electrode under the B, the enhancement of B strength by varying deposition materials and thicknesses was simulated (Figure 4).…”

“…The magnetic field gradient enhanced the magnetohydrodynamic (MHD) flow in the vicinity of ferromagnetic grains, resulting in significantly larger increases in the reduction reaction for Fe and Co than those for Zn. Pan et al16 reported a large enhancement of MC of nearly 30% on the electrochemical oxidation of oxalate in an aqueous (aq) solution. The large enhancement was attributed to the spindependent oxidation of oxalate.…”

Use of magnetic fields in electrochemistry: A selected review

“…The sufficient Fe content favoured the 4-electron pathway (yielding HO•) over the 2-electron pathway (yielding HOO•)[56]. Spin-dependent electrochemistry (SDE) induced enantioselectivity too, as observed for oxalate oxidation[57].…”

Electrochemistry in Magnetic Fields

“…Under 900 mT magnetic field, increasing the CO 2 ‐saturated KHCO 3 solution concentration from 0.1 M to 0.3 M is accompanied by an enhancement of peak currents from 42 % to 90 %, corresponding to an increase in the yield of formic acid from 40 % to 100 %. Similarly, the group also applied the same strategy to oxalate oxidation and obtained a 30 % current increment [60] . The magnetic field effect seems to saturate at a high field, typical of radical pair reactions.…”